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a362032e | 1 | .. SPDX-License-Identifier: GPL-2.0 |
1da177e4 | 2 | |
a362032e MCC |
3 | =================================== |
4 | Linux Ethernet Bonding Driver HOWTO | |
5 | =================================== | |
00354cfb | 6 | |
a362032e MCC |
7 | Latest update: 27 April 2011 |
8 | ||
9 | Initial release: Thomas Davis <tadavis at lbl.gov> | |
10 | ||
11 | Corrections, HA extensions: 2000/10/03-15: | |
1da177e4 | 12 | |
1da177e4 LT |
13 | - Willy Tarreau <willy at meta-x.org> |
14 | - Constantine Gavrilov <const-g at xpert.com> | |
15 | - Chad N. Tindel <ctindel at ieee dot org> | |
16 | - Janice Girouard <girouard at us dot ibm dot com> | |
17 | - Jay Vosburgh <fubar at us dot ibm dot com> | |
18 | ||
19 | Reorganized and updated Feb 2005 by Jay Vosburgh | |
6224e01d | 20 | Added Sysfs information: 2006/04/24 |
a362032e | 21 | |
6224e01d | 22 | - Mitch Williams <mitch.a.williams at intel.com> |
1da177e4 | 23 | |
00354cfb JV |
24 | Introduction |
25 | ============ | |
26 | ||
a362032e | 27 | The Linux bonding driver provides a method for aggregating |
00354cfb JV |
28 | multiple network interfaces into a single logical "bonded" interface. |
29 | The behavior of the bonded interfaces depends upon the mode; generally | |
30 | speaking, modes provide either hot standby or load balancing services. | |
31 | Additionally, link integrity monitoring may be performed. | |
a362032e MCC |
32 | |
33 | The bonding driver originally came from Donald Becker's | |
00354cfb JV |
34 | beowulf patches for kernel 2.0. It has changed quite a bit since, and |
35 | the original tools from extreme-linux and beowulf sites will not work | |
36 | with this version of the driver. | |
1da177e4 | 37 | |
a362032e | 38 | For new versions of the driver, updated userspace tools, and |
00354cfb | 39 | who to ask for help, please follow the links at the end of this file. |
1da177e4 | 40 | |
a362032e | 41 | .. Table of Contents |
1da177e4 | 42 | |
a362032e | 43 | 1. Bonding Driver Installation |
1da177e4 | 44 | |
a362032e | 45 | 2. Bonding Driver Options |
1da177e4 | 46 | |
a362032e MCC |
47 | 3. Configuring Bonding Devices |
48 | 3.1 Configuration with Sysconfig Support | |
49 | 3.1.1 Using DHCP with Sysconfig | |
50 | 3.1.2 Configuring Multiple Bonds with Sysconfig | |
51 | 3.2 Configuration with Initscripts Support | |
52 | 3.2.1 Using DHCP with Initscripts | |
53 | 3.2.2 Configuring Multiple Bonds with Initscripts | |
54 | 3.3 Configuring Bonding Manually with Ifenslave | |
55 | 3.3.1 Configuring Multiple Bonds Manually | |
56 | 3.4 Configuring Bonding Manually via Sysfs | |
57 | 3.5 Configuration with Interfaces Support | |
58 | 3.6 Overriding Configuration for Special Cases | |
59 | 3.7 Configuring LACP for 802.3ad mode in a more secure way | |
1da177e4 | 60 | |
a362032e MCC |
61 | 4. Querying Bonding Configuration |
62 | 4.1 Bonding Configuration | |
63 | 4.2 Network Configuration | |
1da177e4 | 64 | |
a362032e | 65 | 5. Switch Configuration |
1da177e4 | 66 | |
a362032e | 67 | 6. 802.1q VLAN Support |
1da177e4 | 68 | |
a362032e MCC |
69 | 7. Link Monitoring |
70 | 7.1 ARP Monitor Operation | |
71 | 7.2 Configuring Multiple ARP Targets | |
72 | 7.3 MII Monitor Operation | |
1da177e4 | 73 | |
a362032e MCC |
74 | 8. Potential Trouble Sources |
75 | 8.1 Adventures in Routing | |
76 | 8.2 Ethernet Device Renaming | |
77 | 8.3 Painfully Slow Or No Failed Link Detection By Miimon | |
1da177e4 | 78 | |
a362032e | 79 | 9. SNMP agents |
1da177e4 | 80 | |
a362032e | 81 | 10. Promiscuous mode |
1da177e4 | 82 | |
a362032e MCC |
83 | 11. Configuring Bonding for High Availability |
84 | 11.1 High Availability in a Single Switch Topology | |
85 | 11.2 High Availability in a Multiple Switch Topology | |
86 | 11.2.1 HA Bonding Mode Selection for Multiple Switch Topology | |
87 | 11.2.2 HA Link Monitoring for Multiple Switch Topology | |
00354cfb | 88 | |
a362032e MCC |
89 | 12. Configuring Bonding for Maximum Throughput |
90 | 12.1 Maximum Throughput in a Single Switch Topology | |
91 | 12.1.1 MT Bonding Mode Selection for Single Switch Topology | |
92 | 12.1.2 MT Link Monitoring for Single Switch Topology | |
93 | 12.2 Maximum Throughput in a Multiple Switch Topology | |
94 | 12.2.1 MT Bonding Mode Selection for Multiple Switch Topology | |
95 | 12.2.2 MT Link Monitoring for Multiple Switch Topology | |
1da177e4 | 96 | |
a362032e MCC |
97 | 13. Switch Behavior Issues |
98 | 13.1 Link Establishment and Failover Delays | |
99 | 13.2 Duplicated Incoming Packets | |
1da177e4 | 100 | |
a362032e MCC |
101 | 14. Hardware Specific Considerations |
102 | 14.1 IBM BladeCenter | |
1da177e4 | 103 | |
a362032e | 104 | 15. Frequently Asked Questions |
00354cfb | 105 | |
a362032e | 106 | 16. Resources and Links |
1da177e4 LT |
107 | |
108 | ||
109 | 1. Bonding Driver Installation | |
110 | ============================== | |
111 | ||
a362032e | 112 | Most popular distro kernels ship with the bonding driver |
b1098bbe | 113 | already available as a module. If your distro does not, or you |
1da177e4 LT |
114 | have need to compile bonding from source (e.g., configuring and |
115 | installing a mainline kernel from kernel.org), you'll need to perform | |
116 | the following steps: | |
117 | ||
118 | 1.1 Configure and build the kernel with bonding | |
119 | ----------------------------------------------- | |
120 | ||
a362032e | 121 | The current version of the bonding driver is available in the |
1da177e4 | 122 | drivers/net/bonding subdirectory of the most recent kernel source |
00354cfb JV |
123 | (which is available on http://kernel.org). Most users "rolling their |
124 | own" will want to use the most recent kernel from kernel.org. | |
1da177e4 | 125 | |
a362032e | 126 | Configure kernel with "make menuconfig" (or "make xconfig" or |
1da177e4 LT |
127 | "make config"), then select "Bonding driver support" in the "Network |
128 | device support" section. It is recommended that you configure the | |
129 | driver as module since it is currently the only way to pass parameters | |
130 | to the driver or configure more than one bonding device. | |
131 | ||
a362032e | 132 | Build and install the new kernel and modules. |
1da177e4 | 133 | |
b1098bbe | 134 | 1.2 Bonding Control Utility |
a362032e | 135 | --------------------------- |
1da177e4 | 136 | |
a362032e | 137 | It is recommended to configure bonding via iproute2 (netlink) |
b1098bbe | 138 | or sysfs, the old ifenslave control utility is obsolete. |
1da177e4 LT |
139 | |
140 | 2. Bonding Driver Options | |
141 | ========================= | |
142 | ||
a362032e | 143 | Options for the bonding driver are supplied as parameters to the |
9a6c6867 JV |
144 | bonding module at load time, or are specified via sysfs. |
145 | ||
a362032e | 146 | Module options may be given as command line arguments to the |
9a6c6867 | 147 | insmod or modprobe command, but are usually specified in either the |
a362032e | 148 | ``/etc/modprobe.d/*.conf`` configuration files, or in a distro-specific |
970e2486 | 149 | configuration file (some of which are detailed in the next section). |
9a6c6867 | 150 | |
a362032e | 151 | Details on bonding support for sysfs is provided in the |
9a6c6867 | 152 | "Configuring Bonding Manually via Sysfs" section, below. |
1da177e4 | 153 | |
a362032e | 154 | The available bonding driver parameters are listed below. If a |
1da177e4 LT |
155 | parameter is not specified the default value is used. When initially |
156 | configuring a bond, it is recommended "tail -f /var/log/messages" be | |
157 | run in a separate window to watch for bonding driver error messages. | |
158 | ||
a362032e | 159 | It is critical that either the miimon or arp_interval and |
1da177e4 LT |
160 | arp_ip_target parameters be specified, otherwise serious network |
161 | degradation will occur during link failures. Very few devices do not | |
162 | support at least miimon, so there is really no reason not to use it. | |
163 | ||
a362032e | 164 | Options with textual values will accept either the text name |
00354cfb JV |
165 | or, for backwards compatibility, the option value. E.g., |
166 | "mode=802.3ad" and "mode=4" set the same mode. | |
1da177e4 | 167 | |
a362032e | 168 | The parameters are as follows: |
1da177e4 | 169 | |
1ba9ac7c NP |
170 | active_slave |
171 | ||
172 | Specifies the new active slave for modes that support it | |
173 | (active-backup, balance-alb and balance-tlb). Possible values | |
174 | are the name of any currently enslaved interface, or an empty | |
175 | string. If a name is given, the slave and its link must be up in order | |
176 | to be selected as the new active slave. If an empty string is | |
177 | specified, the current active slave is cleared, and a new active | |
178 | slave is selected automatically. | |
179 | ||
180 | Note that this is only available through the sysfs interface. No module | |
181 | parameter by this name exists. | |
182 | ||
183 | The normal value of this option is the name of the currently | |
184 | active slave, or the empty string if there is no active slave or | |
185 | the current mode does not use an active slave. | |
186 | ||
6791e466 MB |
187 | ad_actor_sys_prio |
188 | ||
189 | In an AD system, this specifies the system priority. The allowed range | |
190 | is 1 - 65535. If the value is not specified, it takes 65535 as the | |
191 | default value. | |
192 | ||
193 | This parameter has effect only in 802.3ad mode and is available through | |
194 | SysFs interface. | |
195 | ||
74514957 MB |
196 | ad_actor_system |
197 | ||
198 | In an AD system, this specifies the mac-address for the actor in | |
199 | protocol packet exchanges (LACPDUs). The value cannot be NULL or | |
200 | multicast. It is preferred to have the local-admin bit set for this | |
201 | mac but driver does not enforce it. If the value is not given then | |
202 | system defaults to using the masters' mac address as actors' system | |
203 | address. | |
204 | ||
205 | This parameter has effect only in 802.3ad mode and is available through | |
206 | SysFs interface. | |
207 | ||
fd989c83 JV |
208 | ad_select |
209 | ||
210 | Specifies the 802.3ad aggregation selection logic to use. The | |
211 | possible values and their effects are: | |
212 | ||
213 | stable or 0 | |
214 | ||
215 | The active aggregator is chosen by largest aggregate | |
216 | bandwidth. | |
217 | ||
218 | Reselection of the active aggregator occurs only when all | |
219 | slaves of the active aggregator are down or the active | |
220 | aggregator has no slaves. | |
221 | ||
222 | This is the default value. | |
223 | ||
224 | bandwidth or 1 | |
225 | ||
226 | The active aggregator is chosen by largest aggregate | |
227 | bandwidth. Reselection occurs if: | |
228 | ||
229 | - A slave is added to or removed from the bond | |
230 | ||
231 | - Any slave's link state changes | |
232 | ||
233 | - Any slave's 802.3ad association state changes | |
234 | ||
19f59460 | 235 | - The bond's administrative state changes to up |
fd989c83 JV |
236 | |
237 | count or 2 | |
238 | ||
239 | The active aggregator is chosen by the largest number of | |
240 | ports (slaves). Reselection occurs as described under the | |
241 | "bandwidth" setting, above. | |
242 | ||
243 | The bandwidth and count selection policies permit failover of | |
244 | 802.3ad aggregations when partial failure of the active aggregator | |
245 | occurs. This keeps the aggregator with the highest availability | |
246 | (either in bandwidth or in number of ports) active at all times. | |
247 | ||
248 | This option was added in bonding version 3.4.0. | |
249 | ||
d22a5fc0 MB |
250 | ad_user_port_key |
251 | ||
252 | In an AD system, the port-key has three parts as shown below - | |
253 | ||
a362032e | 254 | ===== ============ |
d22a5fc0 | 255 | Bits Use |
a362032e | 256 | ===== ============ |
d22a5fc0 MB |
257 | 00 Duplex |
258 | 01-05 Speed | |
259 | 06-15 User-defined | |
a362032e | 260 | ===== ============ |
d22a5fc0 MB |
261 | |
262 | This defines the upper 10 bits of the port key. The values can be | |
263 | from 0 - 1023. If not given, the system defaults to 0. | |
264 | ||
265 | This parameter has effect only in 802.3ad mode and is available through | |
266 | SysFs interface. | |
267 | ||
025890b4 NP |
268 | all_slaves_active |
269 | ||
270 | Specifies that duplicate frames (received on inactive ports) should be | |
271 | dropped (0) or delivered (1). | |
272 | ||
273 | Normally, bonding will drop duplicate frames (received on inactive | |
274 | ports), which is desirable for most users. But there are some times | |
275 | it is nice to allow duplicate frames to be delivered. | |
276 | ||
277 | The default value is 0 (drop duplicate frames received on inactive | |
278 | ports). | |
279 | ||
1da177e4 LT |
280 | arp_interval |
281 | ||
00354cfb | 282 | Specifies the ARP link monitoring frequency in milliseconds. |
f5b2b966 JV |
283 | |
284 | The ARP monitor works by periodically checking the slave | |
285 | devices to determine whether they have sent or received | |
286 | traffic recently (the precise criteria depends upon the | |
287 | bonding mode, and the state of the slave). Regular traffic is | |
288 | generated via ARP probes issued for the addresses specified by | |
289 | the arp_ip_target option. | |
290 | ||
291 | This behavior can be modified by the arp_validate option, | |
292 | below. | |
293 | ||
00354cfb JV |
294 | If ARP monitoring is used in an etherchannel compatible mode |
295 | (modes 0 and 2), the switch should be configured in a mode | |
296 | that evenly distributes packets across all links. If the | |
297 | switch is configured to distribute the packets in an XOR | |
1da177e4 LT |
298 | fashion, all replies from the ARP targets will be received on |
299 | the same link which could cause the other team members to | |
00354cfb JV |
300 | fail. ARP monitoring should not be used in conjunction with |
301 | miimon. A value of 0 disables ARP monitoring. The default | |
1da177e4 LT |
302 | value is 0. |
303 | ||
304 | arp_ip_target | |
305 | ||
00354cfb JV |
306 | Specifies the IP addresses to use as ARP monitoring peers when |
307 | arp_interval is > 0. These are the targets of the ARP request | |
308 | sent to determine the health of the link to the targets. | |
309 | Specify these values in ddd.ddd.ddd.ddd format. Multiple IP | |
310 | addresses must be separated by a comma. At least one IP | |
311 | address must be given for ARP monitoring to function. The | |
312 | maximum number of targets that can be specified is 16. The | |
313 | default value is no IP addresses. | |
1da177e4 | 314 | |
f5b2b966 JV |
315 | arp_validate |
316 | ||
317 | Specifies whether or not ARP probes and replies should be | |
52f65ef3 VF |
318 | validated in any mode that supports arp monitoring, or whether |
319 | non-ARP traffic should be filtered (disregarded) for link | |
320 | monitoring purposes. | |
f5b2b966 JV |
321 | |
322 | Possible values are: | |
323 | ||
324 | none or 0 | |
325 | ||
52f65ef3 | 326 | No validation or filtering is performed. |
f5b2b966 JV |
327 | |
328 | active or 1 | |
329 | ||
330 | Validation is performed only for the active slave. | |
331 | ||
332 | backup or 2 | |
333 | ||
334 | Validation is performed only for backup slaves. | |
335 | ||
336 | all or 3 | |
337 | ||
338 | Validation is performed for all slaves. | |
339 | ||
52f65ef3 VF |
340 | filter or 4 |
341 | ||
342 | Filtering is applied to all slaves. No validation is | |
343 | performed. | |
344 | ||
345 | filter_active or 5 | |
346 | ||
347 | Filtering is applied to all slaves, validation is performed | |
348 | only for the active slave. | |
349 | ||
350 | filter_backup or 6 | |
351 | ||
352 | Filtering is applied to all slaves, validation is performed | |
353 | only for backup slaves. | |
354 | ||
355 | Validation: | |
356 | ||
357 | Enabling validation causes the ARP monitor to examine the incoming | |
358 | ARP requests and replies, and only consider a slave to be up if it | |
359 | is receiving the appropriate ARP traffic. | |
360 | ||
361 | For an active slave, the validation checks ARP replies to confirm | |
362 | that they were generated by an arp_ip_target. Since backup slaves | |
363 | do not typically receive these replies, the validation performed | |
364 | for backup slaves is on the broadcast ARP request sent out via the | |
365 | active slave. It is possible that some switch or network | |
366 | configurations may result in situations wherein the backup slaves | |
367 | do not receive the ARP requests; in such a situation, validation | |
368 | of backup slaves must be disabled. | |
369 | ||
370 | The validation of ARP requests on backup slaves is mainly helping | |
371 | bonding to decide which slaves are more likely to work in case of | |
372 | the active slave failure, it doesn't really guarantee that the | |
373 | backup slave will work if it's selected as the next active slave. | |
374 | ||
375 | Validation is useful in network configurations in which multiple | |
376 | bonding hosts are concurrently issuing ARPs to one or more targets | |
377 | beyond a common switch. Should the link between the switch and | |
378 | target fail (but not the switch itself), the probe traffic | |
379 | generated by the multiple bonding instances will fool the standard | |
380 | ARP monitor into considering the links as still up. Use of | |
381 | validation can resolve this, as the ARP monitor will only consider | |
382 | ARP requests and replies associated with its own instance of | |
383 | bonding. | |
384 | ||
385 | Filtering: | |
386 | ||
387 | Enabling filtering causes the ARP monitor to only use incoming ARP | |
388 | packets for link availability purposes. Arriving packets that are | |
389 | not ARPs are delivered normally, but do not count when determining | |
390 | if a slave is available. | |
391 | ||
392 | Filtering operates by only considering the reception of ARP | |
393 | packets (any ARP packet, regardless of source or destination) when | |
394 | determining if a slave has received traffic for link availability | |
395 | purposes. | |
396 | ||
397 | Filtering is useful in network configurations in which significant | |
398 | levels of third party broadcast traffic would fool the standard | |
399 | ARP monitor into considering the links as still up. Use of | |
400 | filtering can resolve this, as only ARP traffic is considered for | |
401 | link availability purposes. | |
f5b2b966 JV |
402 | |
403 | This option was added in bonding version 3.1.0. | |
404 | ||
8599b52e VF |
405 | arp_all_targets |
406 | ||
407 | Specifies the quantity of arp_ip_targets that must be reachable | |
408 | in order for the ARP monitor to consider a slave as being up. | |
409 | This option affects only active-backup mode for slaves with | |
410 | arp_validation enabled. | |
411 | ||
412 | Possible values are: | |
413 | ||
414 | any or 0 | |
415 | ||
416 | consider the slave up only when any of the arp_ip_targets | |
417 | is reachable | |
418 | ||
419 | all or 1 | |
420 | ||
421 | consider the slave up only when all of the arp_ip_targets | |
422 | are reachable | |
423 | ||
1da177e4 LT |
424 | downdelay |
425 | ||
426 | Specifies the time, in milliseconds, to wait before disabling | |
427 | a slave after a link failure has been detected. This option | |
428 | is only valid for the miimon link monitor. The downdelay | |
429 | value should be a multiple of the miimon value; if not, it | |
430 | will be rounded down to the nearest multiple. The default | |
431 | value is 0. | |
432 | ||
dd957c57 JV |
433 | fail_over_mac |
434 | ||
435 | Specifies whether active-backup mode should set all slaves to | |
3915c1e8 JV |
436 | the same MAC address at enslavement (the traditional |
437 | behavior), or, when enabled, perform special handling of the | |
438 | bond's MAC address in accordance with the selected policy. | |
439 | ||
440 | Possible values are: | |
441 | ||
442 | none or 0 | |
443 | ||
444 | This setting disables fail_over_mac, and causes | |
445 | bonding to set all slaves of an active-backup bond to | |
446 | the same MAC address at enslavement time. This is the | |
447 | default. | |
448 | ||
449 | active or 1 | |
450 | ||
451 | The "active" fail_over_mac policy indicates that the | |
452 | MAC address of the bond should always be the MAC | |
453 | address of the currently active slave. The MAC | |
454 | address of the slaves is not changed; instead, the MAC | |
455 | address of the bond changes during a failover. | |
456 | ||
457 | This policy is useful for devices that cannot ever | |
458 | alter their MAC address, or for devices that refuse | |
459 | incoming broadcasts with their own source MAC (which | |
460 | interferes with the ARP monitor). | |
461 | ||
462 | The down side of this policy is that every device on | |
463 | the network must be updated via gratuitous ARP, | |
464 | vs. just updating a switch or set of switches (which | |
465 | often takes place for any traffic, not just ARP | |
466 | traffic, if the switch snoops incoming traffic to | |
467 | update its tables) for the traditional method. If the | |
468 | gratuitous ARP is lost, communication may be | |
469 | disrupted. | |
470 | ||
25985edc | 471 | When this policy is used in conjunction with the mii |
3915c1e8 JV |
472 | monitor, devices which assert link up prior to being |
473 | able to actually transmit and receive are particularly | |
19f59460 | 474 | susceptible to loss of the gratuitous ARP, and an |
3915c1e8 JV |
475 | appropriate updelay setting may be required. |
476 | ||
477 | follow or 2 | |
478 | ||
479 | The "follow" fail_over_mac policy causes the MAC | |
480 | address of the bond to be selected normally (normally | |
481 | the MAC address of the first slave added to the bond). | |
482 | However, the second and subsequent slaves are not set | |
483 | to this MAC address while they are in a backup role; a | |
484 | slave is programmed with the bond's MAC address at | |
485 | failover time (and the formerly active slave receives | |
486 | the newly active slave's MAC address). | |
487 | ||
488 | This policy is useful for multiport devices that | |
489 | either become confused or incur a performance penalty | |
490 | when multiple ports are programmed with the same MAC | |
491 | address. | |
492 | ||
493 | ||
494 | The default policy is none, unless the first slave cannot | |
495 | change its MAC address, in which case the active policy is | |
496 | selected by default. | |
497 | ||
498 | This option may be modified via sysfs only when no slaves are | |
499 | present in the bond. | |
500 | ||
501 | This option was added in bonding version 3.2.0. The "follow" | |
502 | policy was added in bonding version 3.3.0. | |
dd957c57 | 503 | |
1da177e4 LT |
504 | lacp_rate |
505 | ||
506 | Option specifying the rate in which we'll ask our link partner | |
507 | to transmit LACPDU packets in 802.3ad mode. Possible values | |
508 | are: | |
509 | ||
510 | slow or 0 | |
00354cfb | 511 | Request partner to transmit LACPDUs every 30 seconds |
1da177e4 LT |
512 | |
513 | fast or 1 | |
514 | Request partner to transmit LACPDUs every 1 second | |
515 | ||
00354cfb JV |
516 | The default is slow. |
517 | ||
1da177e4 LT |
518 | max_bonds |
519 | ||
520 | Specifies the number of bonding devices to create for this | |
521 | instance of the bonding driver. E.g., if max_bonds is 3, and | |
522 | the bonding driver is not already loaded, then bond0, bond1 | |
b8a9787e JV |
523 | and bond2 will be created. The default value is 1. Specifying |
524 | a value of 0 will load bonding, but will not create any devices. | |
1da177e4 LT |
525 | |
526 | miimon | |
527 | ||
00354cfb JV |
528 | Specifies the MII link monitoring frequency in milliseconds. |
529 | This determines how often the link state of each slave is | |
530 | inspected for link failures. A value of zero disables MII | |
531 | link monitoring. A value of 100 is a good starting point. | |
532 | The use_carrier option, below, affects how the link state is | |
1da177e4 LT |
533 | determined. See the High Availability section for additional |
534 | information. The default value is 0. | |
535 | ||
025890b4 NP |
536 | min_links |
537 | ||
538 | Specifies the minimum number of links that must be active before | |
539 | asserting carrier. It is similar to the Cisco EtherChannel min-links | |
540 | feature. This allows setting the minimum number of member ports that | |
541 | must be up (link-up state) before marking the bond device as up | |
542 | (carrier on). This is useful for situations where higher level services | |
543 | such as clustering want to ensure a minimum number of low bandwidth | |
544 | links are active before switchover. This option only affect 802.3ad | |
545 | mode. | |
546 | ||
547 | The default value is 0. This will cause carrier to be asserted (for | |
548 | 802.3ad mode) whenever there is an active aggregator, regardless of the | |
549 | number of available links in that aggregator. Note that, because an | |
550 | aggregator cannot be active without at least one available link, | |
551 | setting this option to 0 or to 1 has the exact same effect. | |
552 | ||
1da177e4 LT |
553 | mode |
554 | ||
555 | Specifies one of the bonding policies. The default is | |
556 | balance-rr (round robin). Possible values are: | |
557 | ||
558 | balance-rr or 0 | |
559 | ||
560 | Round-robin policy: Transmit packets in sequential | |
561 | order from the first available slave through the | |
562 | last. This mode provides load balancing and fault | |
563 | tolerance. | |
564 | ||
565 | active-backup or 1 | |
566 | ||
567 | Active-backup policy: Only one slave in the bond is | |
568 | active. A different slave becomes active if, and only | |
569 | if, the active slave fails. The bond's MAC address is | |
570 | externally visible on only one port (network adapter) | |
00354cfb JV |
571 | to avoid confusing the switch. |
572 | ||
573 | In bonding version 2.6.2 or later, when a failover | |
574 | occurs in active-backup mode, bonding will issue one | |
575 | or more gratuitous ARPs on the newly active slave. | |
6224e01d | 576 | One gratuitous ARP is issued for the bonding master |
00354cfb JV |
577 | interface and each VLAN interfaces configured above |
578 | it, provided that the interface has at least one IP | |
579 | address configured. Gratuitous ARPs issued for VLAN | |
580 | interfaces are tagged with the appropriate VLAN id. | |
581 | ||
582 | This mode provides fault tolerance. The primary | |
583 | option, documented below, affects the behavior of this | |
584 | mode. | |
1da177e4 LT |
585 | |
586 | balance-xor or 2 | |
587 | ||
00354cfb JV |
588 | XOR policy: Transmit based on the selected transmit |
589 | hash policy. The default policy is a simple [(source | |
92abf750 JX |
590 | MAC address XOR'd with destination MAC address XOR |
591 | packet type ID) modulo slave count]. Alternate transmit | |
592 | policies may be selected via the xmit_hash_policy option, | |
593 | described below. | |
00354cfb JV |
594 | |
595 | This mode provides load balancing and fault tolerance. | |
1da177e4 LT |
596 | |
597 | broadcast or 3 | |
598 | ||
599 | Broadcast policy: transmits everything on all slave | |
600 | interfaces. This mode provides fault tolerance. | |
601 | ||
602 | 802.3ad or 4 | |
603 | ||
604 | IEEE 802.3ad Dynamic link aggregation. Creates | |
605 | aggregation groups that share the same speed and | |
606 | duplex settings. Utilizes all slaves in the active | |
607 | aggregator according to the 802.3ad specification. | |
608 | ||
00354cfb JV |
609 | Slave selection for outgoing traffic is done according |
610 | to the transmit hash policy, which may be changed from | |
611 | the default simple XOR policy via the xmit_hash_policy | |
612 | option, documented below. Note that not all transmit | |
613 | policies may be 802.3ad compliant, particularly in | |
614 | regards to the packet mis-ordering requirements of | |
615 | section 43.2.4 of the 802.3ad standard. Differing | |
616 | peer implementations will have varying tolerances for | |
617 | noncompliance. | |
618 | ||
619 | Prerequisites: | |
1da177e4 LT |
620 | |
621 | 1. Ethtool support in the base drivers for retrieving | |
622 | the speed and duplex of each slave. | |
623 | ||
624 | 2. A switch that supports IEEE 802.3ad Dynamic link | |
625 | aggregation. | |
626 | ||
627 | Most switches will require some type of configuration | |
628 | to enable 802.3ad mode. | |
629 | ||
630 | balance-tlb or 5 | |
631 | ||
632 | Adaptive transmit load balancing: channel bonding that | |
e9f0fb88 MB |
633 | does not require any special switch support. |
634 | ||
635 | In tlb_dynamic_lb=1 mode; the outgoing traffic is | |
636 | distributed according to the current load (computed | |
637 | relative to the speed) on each slave. | |
638 | ||
639 | In tlb_dynamic_lb=0 mode; the load balancing based on | |
640 | current load is disabled and the load is distributed | |
641 | only using the hash distribution. | |
642 | ||
643 | Incoming traffic is received by the current slave. | |
644 | If the receiving slave fails, another slave takes over | |
645 | the MAC address of the failed receiving slave. | |
1da177e4 LT |
646 | |
647 | Prerequisite: | |
648 | ||
649 | Ethtool support in the base drivers for retrieving the | |
650 | speed of each slave. | |
651 | ||
652 | balance-alb or 6 | |
653 | ||
654 | Adaptive load balancing: includes balance-tlb plus | |
655 | receive load balancing (rlb) for IPV4 traffic, and | |
656 | does not require any special switch support. The | |
657 | receive load balancing is achieved by ARP negotiation. | |
658 | The bonding driver intercepts the ARP Replies sent by | |
659 | the local system on their way out and overwrites the | |
660 | source hardware address with the unique hardware | |
661 | address of one of the slaves in the bond such that | |
662 | different peers use different hardware addresses for | |
663 | the server. | |
664 | ||
665 | Receive traffic from connections created by the server | |
666 | is also balanced. When the local system sends an ARP | |
667 | Request the bonding driver copies and saves the peer's | |
668 | IP information from the ARP packet. When the ARP | |
669 | Reply arrives from the peer, its hardware address is | |
670 | retrieved and the bonding driver initiates an ARP | |
671 | reply to this peer assigning it to one of the slaves | |
672 | in the bond. A problematic outcome of using ARP | |
673 | negotiation for balancing is that each time that an | |
674 | ARP request is broadcast it uses the hardware address | |
675 | of the bond. Hence, peers learn the hardware address | |
676 | of the bond and the balancing of receive traffic | |
677 | collapses to the current slave. This is handled by | |
678 | sending updates (ARP Replies) to all the peers with | |
679 | their individually assigned hardware address such that | |
680 | the traffic is redistributed. Receive traffic is also | |
681 | redistributed when a new slave is added to the bond | |
682 | and when an inactive slave is re-activated. The | |
683 | receive load is distributed sequentially (round robin) | |
684 | among the group of highest speed slaves in the bond. | |
685 | ||
686 | When a link is reconnected or a new slave joins the | |
687 | bond the receive traffic is redistributed among all | |
00354cfb | 688 | active slaves in the bond by initiating ARP Replies |
6224e01d | 689 | with the selected MAC address to each of the |
1da177e4 LT |
690 | clients. The updelay parameter (detailed below) must |
691 | be set to a value equal or greater than the switch's | |
692 | forwarding delay so that the ARP Replies sent to the | |
693 | peers will not be blocked by the switch. | |
694 | ||
695 | Prerequisites: | |
696 | ||
697 | 1. Ethtool support in the base drivers for retrieving | |
698 | the speed of each slave. | |
699 | ||
700 | 2. Base driver support for setting the hardware | |
701 | address of a device while it is open. This is | |
702 | required so that there will always be one slave in the | |
703 | team using the bond hardware address (the | |
704 | curr_active_slave) while having a unique hardware | |
705 | address for each slave in the bond. If the | |
706 | curr_active_slave fails its hardware address is | |
707 | swapped with the new curr_active_slave that was | |
708 | chosen. | |
709 | ||
a362032e | 710 | num_grat_arp, |
305d552a BH |
711 | num_unsol_na |
712 | ||
ad246c99 BH |
713 | Specify the number of peer notifications (gratuitous ARPs and |
714 | unsolicited IPv6 Neighbor Advertisements) to be issued after a | |
715 | failover event. As soon as the link is up on the new slave | |
716 | (possibly immediately) a peer notification is sent on the | |
0307d589 VB |
717 | bonding device and each VLAN sub-device. This is repeated at |
718 | the rate specified by peer_notif_delay if the number is | |
719 | greater than 1. | |
ad246c99 BH |
720 | |
721 | The valid range is 0 - 255; the default value is 1. These options | |
722 | affect only the active-backup mode. These options were added for | |
723 | bonding versions 3.3.0 and 3.4.0 respectively. | |
724 | ||
8fb4e139 | 725 | From Linux 3.0 and bonding version 3.7.1, these notifications |
ad246c99 BH |
726 | are generated by the ipv4 and ipv6 code and the numbers of |
727 | repetitions cannot be set independently. | |
305d552a | 728 | |
12465fb8 NA |
729 | packets_per_slave |
730 | ||
731 | Specify the number of packets to transmit through a slave before | |
732 | moving to the next one. When set to 0 then a slave is chosen at | |
733 | random. | |
734 | ||
735 | The valid range is 0 - 65535; the default value is 1. This option | |
736 | has effect only in balance-rr mode. | |
737 | ||
0307d589 VB |
738 | peer_notif_delay |
739 | ||
a362032e MCC |
740 | Specify the delay, in milliseconds, between each peer |
741 | notification (gratuitous ARP and unsolicited IPv6 Neighbor | |
742 | Advertisement) when they are issued after a failover event. | |
743 | This delay should be a multiple of the link monitor interval | |
744 | (arp_interval or miimon, whichever is active). The default | |
745 | value is 0 which means to match the value of the link monitor | |
746 | interval. | |
0307d589 | 747 | |
1da177e4 LT |
748 | primary |
749 | ||
750 | A string (eth0, eth2, etc) specifying which slave is the | |
751 | primary device. The specified device will always be the | |
752 | active slave while it is available. Only when the primary is | |
753 | off-line will alternate devices be used. This is useful when | |
754 | one slave is preferred over another, e.g., when one slave has | |
755 | higher throughput than another. | |
756 | ||
e1d206a7 | 757 | The primary option is only valid for active-backup(1), |
758 | balance-tlb (5) and balance-alb (6) mode. | |
1da177e4 | 759 | |
a549952a JP |
760 | primary_reselect |
761 | ||
762 | Specifies the reselection policy for the primary slave. This | |
763 | affects how the primary slave is chosen to become the active slave | |
764 | when failure of the active slave or recovery of the primary slave | |
765 | occurs. This option is designed to prevent flip-flopping between | |
766 | the primary slave and other slaves. Possible values are: | |
767 | ||
768 | always or 0 (default) | |
769 | ||
770 | The primary slave becomes the active slave whenever it | |
771 | comes back up. | |
772 | ||
773 | better or 1 | |
774 | ||
775 | The primary slave becomes the active slave when it comes | |
776 | back up, if the speed and duplex of the primary slave is | |
777 | better than the speed and duplex of the current active | |
778 | slave. | |
779 | ||
780 | failure or 2 | |
781 | ||
782 | The primary slave becomes the active slave only if the | |
783 | current active slave fails and the primary slave is up. | |
784 | ||
785 | The primary_reselect setting is ignored in two cases: | |
786 | ||
787 | If no slaves are active, the first slave to recover is | |
788 | made the active slave. | |
789 | ||
790 | When initially enslaved, the primary slave is always made | |
791 | the active slave. | |
792 | ||
793 | Changing the primary_reselect policy via sysfs will cause an | |
794 | immediate selection of the best active slave according to the new | |
795 | policy. This may or may not result in a change of the active | |
796 | slave, depending upon the circumstances. | |
797 | ||
798 | This option was added for bonding version 3.6.0. | |
799 | ||
e9f0fb88 MB |
800 | tlb_dynamic_lb |
801 | ||
802 | Specifies if dynamic shuffling of flows is enabled in tlb | |
803 | mode. The value has no effect on any other modes. | |
804 | ||
805 | The default behavior of tlb mode is to shuffle active flows across | |
806 | slaves based on the load in that interval. This gives nice lb | |
807 | characteristics but can cause packet reordering. If re-ordering is | |
808 | a concern use this variable to disable flow shuffling and rely on | |
809 | load balancing provided solely by the hash distribution. | |
810 | xmit-hash-policy can be used to select the appropriate hashing for | |
811 | the setup. | |
812 | ||
813 | The sysfs entry can be used to change the setting per bond device | |
814 | and the initial value is derived from the module parameter. The | |
815 | sysfs entry is allowed to be changed only if the bond device is | |
816 | down. | |
817 | ||
818 | The default value is "1" that enables flow shuffling while value "0" | |
819 | disables it. This option was added in bonding driver 3.7.1 | |
820 | ||
821 | ||
1da177e4 LT |
822 | updelay |
823 | ||
824 | Specifies the time, in milliseconds, to wait before enabling a | |
825 | slave after a link recovery has been detected. This option is | |
826 | only valid for the miimon link monitor. The updelay value | |
827 | should be a multiple of the miimon value; if not, it will be | |
828 | rounded down to the nearest multiple. The default value is 0. | |
829 | ||
830 | use_carrier | |
831 | ||
832 | Specifies whether or not miimon should use MII or ETHTOOL | |
833 | ioctls vs. netif_carrier_ok() to determine the link | |
834 | status. The MII or ETHTOOL ioctls are less efficient and | |
835 | utilize a deprecated calling sequence within the kernel. The | |
836 | netif_carrier_ok() relies on the device driver to maintain its | |
837 | state with netif_carrier_on/off; at this writing, most, but | |
838 | not all, device drivers support this facility. | |
839 | ||
840 | If bonding insists that the link is up when it should not be, | |
841 | it may be that your network device driver does not support | |
842 | netif_carrier_on/off. The default state for netif_carrier is | |
843 | "carrier on," so if a driver does not support netif_carrier, | |
844 | it will appear as if the link is always up. In this case, | |
845 | setting use_carrier to 0 will cause bonding to revert to the | |
846 | MII / ETHTOOL ioctl method to determine the link state. | |
847 | ||
848 | A value of 1 enables the use of netif_carrier_ok(), a value of | |
b3c898e2 DB |
849 | 0 will use the deprecated MII / ETHTOOL ioctls. The default |
850 | value is 1. | |
1da177e4 | 851 | |
00354cfb JV |
852 | xmit_hash_policy |
853 | ||
854 | Selects the transmit hash policy to use for slave selection in | |
f05b42ea | 855 | balance-xor, 802.3ad, and tlb modes. Possible values are: |
00354cfb JV |
856 | |
857 | layer2 | |
858 | ||
92abf750 JX |
859 | Uses XOR of hardware MAC addresses and packet type ID |
860 | field to generate the hash. The formula is | |
00354cfb | 861 | |
92abf750 JX |
862 | hash = source MAC XOR destination MAC XOR packet type ID |
863 | slave number = hash modulo slave count | |
00354cfb JV |
864 | |
865 | This algorithm will place all traffic to a particular | |
866 | network peer on the same slave. | |
867 | ||
868 | This algorithm is 802.3ad compliant. | |
869 | ||
6f6652be JV |
870 | layer2+3 |
871 | ||
872 | This policy uses a combination of layer2 and layer3 | |
873 | protocol information to generate the hash. | |
874 | ||
875 | Uses XOR of hardware MAC addresses and IP addresses to | |
7a6afab1 | 876 | generate the hash. The formula is |
6f6652be | 877 | |
92abf750 | 878 | hash = source MAC XOR destination MAC XOR packet type ID |
7a6afab1 NA |
879 | hash = hash XOR source IP XOR destination IP |
880 | hash = hash XOR (hash RSHIFT 16) | |
881 | hash = hash XOR (hash RSHIFT 8) | |
882 | And then hash is reduced modulo slave count. | |
6f6652be | 883 | |
7a6afab1 NA |
884 | If the protocol is IPv6 then the source and destination |
885 | addresses are first hashed using ipv6_addr_hash. | |
6b923cb7 | 886 | |
6f6652be JV |
887 | This algorithm will place all traffic to a particular |
888 | network peer on the same slave. For non-IP traffic, | |
889 | the formula is the same as for the layer2 transmit | |
890 | hash policy. | |
891 | ||
892 | This policy is intended to provide a more balanced | |
893 | distribution of traffic than layer2 alone, especially | |
894 | in environments where a layer3 gateway device is | |
895 | required to reach most destinations. | |
896 | ||
d9195881 | 897 | This algorithm is 802.3ad compliant. |
6f6652be | 898 | |
00354cfb JV |
899 | layer3+4 |
900 | ||
901 | This policy uses upper layer protocol information, | |
902 | when available, to generate the hash. This allows for | |
903 | traffic to a particular network peer to span multiple | |
904 | slaves, although a single connection will not span | |
905 | multiple slaves. | |
906 | ||
7a6afab1 | 907 | The formula for unfragmented TCP and UDP packets is |
00354cfb | 908 | |
7a6afab1 NA |
909 | hash = source port, destination port (as in the header) |
910 | hash = hash XOR source IP XOR destination IP | |
911 | hash = hash XOR (hash RSHIFT 16) | |
912 | hash = hash XOR (hash RSHIFT 8) | |
913 | And then hash is reduced modulo slave count. | |
6b923cb7 | 914 | |
7a6afab1 NA |
915 | If the protocol is IPv6 then the source and destination |
916 | addresses are first hashed using ipv6_addr_hash. | |
6b923cb7 JE |
917 | |
918 | For fragmented TCP or UDP packets and all other IPv4 and | |
919 | IPv6 protocol traffic, the source and destination port | |
00354cfb JV |
920 | information is omitted. For non-IP traffic, the |
921 | formula is the same as for the layer2 transmit hash | |
922 | policy. | |
923 | ||
00354cfb JV |
924 | This algorithm is not fully 802.3ad compliant. A |
925 | single TCP or UDP conversation containing both | |
926 | fragmented and unfragmented packets will see packets | |
927 | striped across two interfaces. This may result in out | |
928 | of order delivery. Most traffic types will not meet | |
929 | this criteria, as TCP rarely fragments traffic, and | |
930 | most UDP traffic is not involved in extended | |
931 | conversations. Other implementations of 802.3ad may | |
932 | or may not tolerate this noncompliance. | |
933 | ||
7a6afab1 NA |
934 | encap2+3 |
935 | ||
936 | This policy uses the same formula as layer2+3 but it | |
937 | relies on skb_flow_dissect to obtain the header fields | |
938 | which might result in the use of inner headers if an | |
939 | encapsulation protocol is used. For example this will | |
940 | improve the performance for tunnel users because the | |
941 | packets will be distributed according to the encapsulated | |
942 | flows. | |
943 | ||
944 | encap3+4 | |
945 | ||
946 | This policy uses the same formula as layer3+4 but it | |
947 | relies on skb_flow_dissect to obtain the header fields | |
948 | which might result in the use of inner headers if an | |
949 | encapsulation protocol is used. For example this will | |
950 | improve the performance for tunnel users because the | |
951 | packets will be distributed according to the encapsulated | |
952 | flows. | |
953 | ||
00354cfb | 954 | The default value is layer2. This option was added in bonding |
6f6652be JV |
955 | version 2.6.3. In earlier versions of bonding, this parameter |
956 | does not exist, and the layer2 policy is the only policy. The | |
957 | layer2+3 value was added for bonding version 3.2.2. | |
1da177e4 | 958 | |
c2952c31 FL |
959 | resend_igmp |
960 | ||
961 | Specifies the number of IGMP membership reports to be issued after | |
962 | a failover event. One membership report is issued immediately after | |
963 | the failover, subsequent packets are sent in each 200ms interval. | |
964 | ||
94265cf5 FL |
965 | The valid range is 0 - 255; the default value is 1. A value of 0 |
966 | prevents the IGMP membership report from being issued in response | |
967 | to the failover event. | |
968 | ||
969 | This option is useful for bonding modes balance-rr (0), active-backup | |
970 | (1), balance-tlb (5) and balance-alb (6), in which a failover can | |
971 | switch the IGMP traffic from one slave to another. Therefore a fresh | |
972 | IGMP report must be issued to cause the switch to forward the incoming | |
973 | IGMP traffic over the newly selected slave. | |
974 | ||
975 | This option was added for bonding version 3.7.0. | |
1da177e4 | 976 | |
84a6a0ac | 977 | lp_interval |
978 | ||
979 | Specifies the number of seconds between instances where the bonding | |
980 | driver sends learning packets to each slaves peer switch. | |
981 | ||
982 | The valid range is 1 - 0x7fffffff; the default value is 1. This Option | |
983 | has effect only in balance-tlb and balance-alb modes. | |
984 | ||
1da177e4 LT |
985 | 3. Configuring Bonding Devices |
986 | ============================== | |
987 | ||
a362032e | 988 | You can configure bonding using either your distro's network |
b1098bbe | 989 | initialization scripts, or manually using either iproute2 or the |
de221bd5 NP |
990 | sysfs interface. Distros generally use one of three packages for the |
991 | network initialization scripts: initscripts, sysconfig or interfaces. | |
992 | Recent versions of these packages have support for bonding, while older | |
6224e01d | 993 | versions do not. |
1da177e4 | 994 | |
a362032e | 995 | We will first describe the options for configuring bonding for |
de221bd5 NP |
996 | distros using versions of initscripts, sysconfig and interfaces with full |
997 | or partial support for bonding, then provide information on enabling | |
1da177e4 LT |
998 | bonding without support from the network initialization scripts (i.e., |
999 | older versions of initscripts or sysconfig). | |
1000 | ||
a362032e | 1001 | If you're unsure whether your distro uses sysconfig, |
de221bd5 | 1002 | initscripts or interfaces, or don't know if it's new enough, have no fear. |
1da177e4 LT |
1003 | Determining this is fairly straightforward. |
1004 | ||
a362032e | 1005 | First, look for a file called interfaces in /etc/network directory. |
de221bd5 NP |
1006 | If this file is present in your system, then your system use interfaces. See |
1007 | Configuration with Interfaces Support. | |
1008 | ||
a362032e | 1009 | Else, issue the command:: |
1da177e4 | 1010 | |
a362032e | 1011 | $ rpm -qf /sbin/ifup |
1da177e4 | 1012 | |
a362032e | 1013 | It will respond with a line of text starting with either |
1da177e4 LT |
1014 | "initscripts" or "sysconfig," followed by some numbers. This is the |
1015 | package that provides your network initialization scripts. | |
1016 | ||
a362032e MCC |
1017 | Next, to determine if your installation supports bonding, |
1018 | issue the command:: | |
1da177e4 | 1019 | |
a362032e | 1020 | $ grep ifenslave /sbin/ifup |
1da177e4 | 1021 | |
a362032e | 1022 | If this returns any matches, then your initscripts or |
1da177e4 LT |
1023 | sysconfig has support for bonding. |
1024 | ||
6224e01d | 1025 | 3.1 Configuration with Sysconfig Support |
1da177e4 LT |
1026 | ---------------------------------------- |
1027 | ||
a362032e | 1028 | This section applies to distros using a version of sysconfig |
1da177e4 LT |
1029 | with bonding support, for example, SuSE Linux Enterprise Server 9. |
1030 | ||
a362032e | 1031 | SuSE SLES 9's networking configuration system does support |
1da177e4 | 1032 | bonding, however, at this writing, the YaST system configuration |
6224e01d | 1033 | front end does not provide any means to work with bonding devices. |
1da177e4 LT |
1034 | Bonding devices can be managed by hand, however, as follows. |
1035 | ||
a362032e | 1036 | First, if they have not already been configured, configure the |
1da177e4 LT |
1037 | slave devices. On SLES 9, this is most easily done by running the |
1038 | yast2 sysconfig configuration utility. The goal is for to create an | |
1039 | ifcfg-id file for each slave device. The simplest way to accomplish | |
00354cfb JV |
1040 | this is to configure the devices for DHCP (this is only to get the |
1041 | file ifcfg-id file created; see below for some issues with DHCP). The | |
a362032e | 1042 | name of the configuration file for each device will be of the form:: |
1da177e4 | 1043 | |
a362032e | 1044 | ifcfg-id-xx:xx:xx:xx:xx:xx |
1da177e4 | 1045 | |
a362032e | 1046 | Where the "xx" portion will be replaced with the digits from |
1da177e4 LT |
1047 | the device's permanent MAC address. |
1048 | ||
a362032e | 1049 | Once the set of ifcfg-id-xx:xx:xx:xx:xx:xx files has been |
1da177e4 LT |
1050 | created, it is necessary to edit the configuration files for the slave |
1051 | devices (the MAC addresses correspond to those of the slave devices). | |
00354cfb | 1052 | Before editing, the file will contain multiple lines, and will look |
a362032e | 1053 | something like this:: |
1da177e4 | 1054 | |
a362032e MCC |
1055 | BOOTPROTO='dhcp' |
1056 | STARTMODE='on' | |
1057 | USERCTL='no' | |
1058 | UNIQUE='XNzu.WeZGOGF+4wE' | |
1059 | _nm_name='bus-pci-0001:61:01.0' | |
1da177e4 | 1060 | |
a362032e | 1061 | Change the BOOTPROTO and STARTMODE lines to the following:: |
1da177e4 | 1062 | |
a362032e MCC |
1063 | BOOTPROTO='none' |
1064 | STARTMODE='off' | |
1da177e4 | 1065 | |
a362032e | 1066 | Do not alter the UNIQUE or _nm_name lines. Remove any other |
1da177e4 LT |
1067 | lines (USERCTL, etc). |
1068 | ||
a362032e | 1069 | Once the ifcfg-id-xx:xx:xx:xx:xx:xx files have been modified, |
1da177e4 LT |
1070 | it's time to create the configuration file for the bonding device |
1071 | itself. This file is named ifcfg-bondX, where X is the number of the | |
1072 | bonding device to create, starting at 0. The first such file is | |
1073 | ifcfg-bond0, the second is ifcfg-bond1, and so on. The sysconfig | |
1074 | network configuration system will correctly start multiple instances | |
1075 | of bonding. | |
1076 | ||
a362032e MCC |
1077 | The contents of the ifcfg-bondX file is as follows:: |
1078 | ||
1079 | BOOTPROTO="static" | |
1080 | BROADCAST="10.0.2.255" | |
1081 | IPADDR="10.0.2.10" | |
1082 | NETMASK="255.255.0.0" | |
1083 | NETWORK="10.0.2.0" | |
1084 | REMOTE_IPADDR="" | |
1085 | STARTMODE="onboot" | |
1086 | BONDING_MASTER="yes" | |
1087 | BONDING_MODULE_OPTS="mode=active-backup miimon=100" | |
1088 | BONDING_SLAVE0="eth0" | |
1089 | BONDING_SLAVE1="bus-pci-0000:06:08.1" | |
1090 | ||
1091 | Replace the sample BROADCAST, IPADDR, NETMASK and NETWORK | |
1da177e4 LT |
1092 | values with the appropriate values for your network. |
1093 | ||
a362032e | 1094 | The STARTMODE specifies when the device is brought online. |
1da177e4 LT |
1095 | The possible values are: |
1096 | ||
a362032e MCC |
1097 | ======== ====================================================== |
1098 | onboot The device is started at boot time. If you're not | |
1da177e4 LT |
1099 | sure, this is probably what you want. |
1100 | ||
a362032e | 1101 | manual The device is started only when ifup is called |
1da177e4 LT |
1102 | manually. Bonding devices may be configured this |
1103 | way if you do not wish them to start automatically | |
1104 | at boot for some reason. | |
1105 | ||
a362032e | 1106 | hotplug The device is started by a hotplug event. This is not |
1da177e4 LT |
1107 | a valid choice for a bonding device. |
1108 | ||
a362032e MCC |
1109 | off or The device configuration is ignored. |
1110 | ignore | |
1111 | ======== ====================================================== | |
1da177e4 | 1112 | |
a362032e | 1113 | The line BONDING_MASTER='yes' indicates that the device is a |
1da177e4 LT |
1114 | bonding master device. The only useful value is "yes." |
1115 | ||
a362032e | 1116 | The contents of BONDING_MODULE_OPTS are supplied to the |
1da177e4 LT |
1117 | instance of the bonding module for this device. Specify the options |
1118 | for the bonding mode, link monitoring, and so on here. Do not include | |
1119 | the max_bonds bonding parameter; this will confuse the configuration | |
1120 | system if you have multiple bonding devices. | |
1121 | ||
a362032e | 1122 | Finally, supply one BONDING_SLAVEn="slave device" for each |
00354cfb JV |
1123 | slave. where "n" is an increasing value, one for each slave. The |
1124 | "slave device" is either an interface name, e.g., "eth0", or a device | |
1125 | specifier for the network device. The interface name is easier to | |
1126 | find, but the ethN names are subject to change at boot time if, e.g., | |
1127 | a device early in the sequence has failed. The device specifiers | |
1128 | (bus-pci-0000:06:08.1 in the example above) specify the physical | |
1129 | network device, and will not change unless the device's bus location | |
1130 | changes (for example, it is moved from one PCI slot to another). The | |
1131 | example above uses one of each type for demonstration purposes; most | |
1132 | configurations will choose one or the other for all slave devices. | |
1da177e4 | 1133 | |
a362032e | 1134 | When all configuration files have been modified or created, |
1da177e4 | 1135 | networking must be restarted for the configuration changes to take |
a362032e | 1136 | effect. This can be accomplished via the following:: |
1da177e4 | 1137 | |
a362032e | 1138 | # /etc/init.d/network restart |
1da177e4 | 1139 | |
a362032e | 1140 | Note that the network control script (/sbin/ifdown) will |
1da177e4 LT |
1141 | remove the bonding module as part of the network shutdown processing, |
1142 | so it is not necessary to remove the module by hand if, e.g., the | |
00354cfb | 1143 | module parameters have changed. |
1da177e4 | 1144 | |
a362032e | 1145 | Also, at this writing, YaST/YaST2 will not manage bonding |
1da177e4 LT |
1146 | devices (they do not show bonding interfaces on its list of network |
1147 | devices). It is necessary to edit the configuration file by hand to | |
1148 | change the bonding configuration. | |
1149 | ||
a362032e MCC |
1150 | Additional general options and details of the ifcfg file |
1151 | format can be found in an example ifcfg template file:: | |
1da177e4 | 1152 | |
a362032e | 1153 | /etc/sysconfig/network/ifcfg.template |
1da177e4 | 1154 | |
a362032e | 1155 | Note that the template does not document the various ``BONDING_*`` |
1da177e4 LT |
1156 | settings described above, but does describe many of the other options. |
1157 | ||
6224e01d | 1158 | 3.1.1 Using DHCP with Sysconfig |
00354cfb JV |
1159 | ------------------------------- |
1160 | ||
a362032e | 1161 | Under sysconfig, configuring a device with BOOTPROTO='dhcp' |
00354cfb JV |
1162 | will cause it to query DHCP for its IP address information. At this |
1163 | writing, this does not function for bonding devices; the scripts | |
1164 | attempt to obtain the device address from DHCP prior to adding any of | |
1165 | the slave devices. Without active slaves, the DHCP requests are not | |
1166 | sent to the network. | |
1167 | ||
6224e01d | 1168 | 3.1.2 Configuring Multiple Bonds with Sysconfig |
00354cfb JV |
1169 | ----------------------------------------------- |
1170 | ||
a362032e | 1171 | The sysconfig network initialization system is capable of |
00354cfb JV |
1172 | handling multiple bonding devices. All that is necessary is for each |
1173 | bonding instance to have an appropriately configured ifcfg-bondX file | |
1174 | (as described above). Do not specify the "max_bonds" parameter to any | |
1175 | instance of bonding, as this will confuse sysconfig. If you require | |
1176 | multiple bonding devices with identical parameters, create multiple | |
1177 | ifcfg-bondX files. | |
1178 | ||
a362032e | 1179 | Because the sysconfig scripts supply the bonding module |
00354cfb | 1180 | options in the ifcfg-bondX file, it is not necessary to add them to |
a362032e | 1181 | the system ``/etc/modules.d/*.conf`` configuration files. |
00354cfb | 1182 | |
6224e01d | 1183 | 3.2 Configuration with Initscripts Support |
1da177e4 LT |
1184 | ------------------------------------------ |
1185 | ||
a362032e | 1186 | This section applies to distros using a recent version of |
9a6c6867 JV |
1187 | initscripts with bonding support, for example, Red Hat Enterprise Linux |
1188 | version 3 or later, Fedora, etc. On these systems, the network | |
1189 | initialization scripts have knowledge of bonding, and can be configured to | |
1190 | control bonding devices. Note that older versions of the initscripts | |
1191 | package have lower levels of support for bonding; this will be noted where | |
1192 | applicable. | |
1da177e4 | 1193 | |
a362032e | 1194 | These distros will not automatically load the network adapter |
1da177e4 LT |
1195 | driver unless the ethX device is configured with an IP address. |
1196 | Because of this constraint, users must manually configure a | |
1197 | network-script file for all physical adapters that will be members of | |
1198 | a bondX link. Network script files are located in the directory: | |
1199 | ||
1200 | /etc/sysconfig/network-scripts | |
1201 | ||
a362032e | 1202 | The file name must be prefixed with "ifcfg-eth" and suffixed |
1da177e4 LT |
1203 | with the adapter's physical adapter number. For example, the script |
1204 | for eth0 would be named /etc/sysconfig/network-scripts/ifcfg-eth0. | |
a362032e | 1205 | Place the following text in the file:: |
1da177e4 | 1206 | |
a362032e MCC |
1207 | DEVICE=eth0 |
1208 | USERCTL=no | |
1209 | ONBOOT=yes | |
1210 | MASTER=bond0 | |
1211 | SLAVE=yes | |
1212 | BOOTPROTO=none | |
1da177e4 | 1213 | |
a362032e | 1214 | The DEVICE= line will be different for every ethX device and |
1da177e4 LT |
1215 | must correspond with the name of the file, i.e., ifcfg-eth1 must have |
1216 | a device line of DEVICE=eth1. The setting of the MASTER= line will | |
1217 | also depend on the final bonding interface name chosen for your bond. | |
1218 | As with other network devices, these typically start at 0, and go up | |
1219 | one for each device, i.e., the first bonding instance is bond0, the | |
1220 | second is bond1, and so on. | |
1221 | ||
a362032e | 1222 | Next, create a bond network script. The file name for this |
1da177e4 LT |
1223 | script will be /etc/sysconfig/network-scripts/ifcfg-bondX where X is |
1224 | the number of the bond. For bond0 the file is named "ifcfg-bond0", | |
1225 | for bond1 it is named "ifcfg-bond1", and so on. Within that file, | |
a362032e MCC |
1226 | place the following text:: |
1227 | ||
1228 | DEVICE=bond0 | |
1229 | IPADDR=192.168.1.1 | |
1230 | NETMASK=255.255.255.0 | |
1231 | NETWORK=192.168.1.0 | |
1232 | BROADCAST=192.168.1.255 | |
1233 | ONBOOT=yes | |
1234 | BOOTPROTO=none | |
1235 | USERCTL=no | |
1236 | ||
1237 | Be sure to change the networking specific lines (IPADDR, | |
1da177e4 LT |
1238 | NETMASK, NETWORK and BROADCAST) to match your network configuration. |
1239 | ||
a362032e | 1240 | For later versions of initscripts, such as that found with Fedora |
3f8b4b13 AG |
1241 | 7 (or later) and Red Hat Enterprise Linux version 5 (or later), it is possible, |
1242 | and, indeed, preferable, to specify the bonding options in the ifcfg-bond0 | |
a362032e | 1243 | file, e.g. a line of the format:: |
9a6c6867 | 1244 | |
a362032e | 1245 | BONDING_OPTS="mode=active-backup arp_interval=60 arp_ip_target=192.168.1.254" |
9a6c6867 | 1246 | |
a362032e | 1247 | will configure the bond with the specified options. The options |
9a6c6867 | 1248 | specified in BONDING_OPTS are identical to the bonding module parameters |
3f8b4b13 AG |
1249 | except for the arp_ip_target field when using versions of initscripts older |
1250 | than and 8.57 (Fedora 8) and 8.45.19 (Red Hat Enterprise Linux 5.2). When | |
1251 | using older versions each target should be included as a separate option and | |
1252 | should be preceded by a '+' to indicate it should be added to the list of | |
a362032e | 1253 | queried targets, e.g.,:: |
9a6c6867 | 1254 | |
a362032e | 1255 | arp_ip_target=+192.168.1.1 arp_ip_target=+192.168.1.2 |
9a6c6867 | 1256 | |
a362032e MCC |
1257 | is the proper syntax to specify multiple targets. When specifying |
1258 | options via BONDING_OPTS, it is not necessary to edit | |
1259 | ``/etc/modprobe.d/*.conf``. | |
9a6c6867 | 1260 | |
a362032e | 1261 | For even older versions of initscripts that do not support |
970e2486 LDM |
1262 | BONDING_OPTS, it is necessary to edit /etc/modprobe.d/*.conf, depending upon |
1263 | your distro) to load the bonding module with your desired options when the | |
1264 | bond0 interface is brought up. The following lines in /etc/modprobe.d/*.conf | |
1265 | will load the bonding module, and select its options: | |
1da177e4 | 1266 | |
a362032e MCC |
1267 | alias bond0 bonding |
1268 | options bond0 mode=balance-alb miimon=100 | |
1da177e4 | 1269 | |
a362032e | 1270 | Replace the sample parameters with the appropriate set of |
1da177e4 LT |
1271 | options for your configuration. |
1272 | ||
a362032e | 1273 | Finally run "/etc/rc.d/init.d/network restart" as root. This |
1da177e4 LT |
1274 | will restart the networking subsystem and your bond link should be now |
1275 | up and running. | |
1276 | ||
6224e01d | 1277 | 3.2.1 Using DHCP with Initscripts |
00354cfb JV |
1278 | --------------------------------- |
1279 | ||
a362032e | 1280 | Recent versions of initscripts (the versions supplied with Fedora |
9a6c6867 JV |
1281 | Core 3 and Red Hat Enterprise Linux 4, or later versions, are reported to |
1282 | work) have support for assigning IP information to bonding devices via | |
1283 | DHCP. | |
00354cfb | 1284 | |
a362032e | 1285 | To configure bonding for DHCP, configure it as described |
00354cfb JV |
1286 | above, except replace the line "BOOTPROTO=none" with "BOOTPROTO=dhcp" |
1287 | and add a line consisting of "TYPE=Bonding". Note that the TYPE value | |
1288 | is case sensitive. | |
1289 | ||
6224e01d | 1290 | 3.2.2 Configuring Multiple Bonds with Initscripts |
00354cfb JV |
1291 | ------------------------------------------------- |
1292 | ||
a362032e | 1293 | Initscripts packages that are included with Fedora 7 and Red Hat |
9a6c6867 JV |
1294 | Enterprise Linux 5 support multiple bonding interfaces by simply |
1295 | specifying the appropriate BONDING_OPTS= in ifcfg-bondX where X is the | |
1296 | number of the bond. This support requires sysfs support in the kernel, | |
1297 | and a bonding driver of version 3.0.0 or later. Other configurations may | |
1298 | not support this method for specifying multiple bonding interfaces; for | |
1299 | those instances, see the "Configuring Multiple Bonds Manually" section, | |
1300 | below. | |
1da177e4 | 1301 | |
b1098bbe | 1302 | 3.3 Configuring Bonding Manually with iproute2 |
6224e01d | 1303 | ----------------------------------------------- |
1da177e4 | 1304 | |
a362032e | 1305 | This section applies to distros whose network initialization |
1da177e4 LT |
1306 | scripts (the sysconfig or initscripts package) do not have specific |
1307 | knowledge of bonding. One such distro is SuSE Linux Enterprise Server | |
1308 | version 8. | |
1309 | ||
a362032e | 1310 | The general method for these systems is to place the bonding |
970e2486 | 1311 | module parameters into a config file in /etc/modprobe.d/ (as |
00354cfb | 1312 | appropriate for the installed distro), then add modprobe and/or |
b1098bbe | 1313 | `ip link` commands to the system's global init script. The name of |
00354cfb | 1314 | the global init script differs; for sysconfig, it is |
1da177e4 LT |
1315 | /etc/init.d/boot.local and for initscripts it is /etc/rc.d/rc.local. |
1316 | ||
a362032e | 1317 | For example, if you wanted to make a simple bond of two e100 |
1da177e4 LT |
1318 | devices (presumed to be eth0 and eth1), and have it persist across |
1319 | reboots, edit the appropriate file (/etc/init.d/boot.local or | |
a362032e | 1320 | /etc/rc.d/rc.local), and add the following:: |
1da177e4 | 1321 | |
a362032e MCC |
1322 | modprobe bonding mode=balance-alb miimon=100 |
1323 | modprobe e100 | |
1324 | ifconfig bond0 192.168.1.1 netmask 255.255.255.0 up | |
1325 | ip link set eth0 master bond0 | |
1326 | ip link set eth1 master bond0 | |
1da177e4 | 1327 | |
a362032e | 1328 | Replace the example bonding module parameters and bond0 |
1da177e4 | 1329 | network configuration (IP address, netmask, etc) with the appropriate |
00354cfb | 1330 | values for your configuration. |
1da177e4 | 1331 | |
a362032e | 1332 | Unfortunately, this method will not provide support for the |
1da177e4 | 1333 | ifup and ifdown scripts on the bond devices. To reload the bonding |
a362032e | 1334 | configuration, it is necessary to run the initialization script, e.g.,:: |
1da177e4 | 1335 | |
a362032e | 1336 | # /etc/init.d/boot.local |
1da177e4 | 1337 | |
a362032e | 1338 | or:: |
1da177e4 | 1339 | |
a362032e | 1340 | # /etc/rc.d/rc.local |
1da177e4 | 1341 | |
a362032e | 1342 | It may be desirable in such a case to create a separate script |
1da177e4 LT |
1343 | which only initializes the bonding configuration, then call that |
1344 | separate script from within boot.local. This allows for bonding to be | |
1345 | enabled without re-running the entire global init script. | |
1346 | ||
a362032e | 1347 | To shut down the bonding devices, it is necessary to first |
1da177e4 LT |
1348 | mark the bonding device itself as being down, then remove the |
1349 | appropriate device driver modules. For our example above, you can do | |
a362032e | 1350 | the following:: |
1da177e4 | 1351 | |
a362032e MCC |
1352 | # ifconfig bond0 down |
1353 | # rmmod bonding | |
1354 | # rmmod e100 | |
1da177e4 | 1355 | |
a362032e | 1356 | Again, for convenience, it may be desirable to create a script |
1da177e4 LT |
1357 | with these commands. |
1358 | ||
1359 | ||
00354cfb JV |
1360 | 3.3.1 Configuring Multiple Bonds Manually |
1361 | ----------------------------------------- | |
1da177e4 | 1362 | |
a362032e | 1363 | This section contains information on configuring multiple |
00354cfb JV |
1364 | bonding devices with differing options for those systems whose network |
1365 | initialization scripts lack support for configuring multiple bonds. | |
1366 | ||
a362032e | 1367 | If you require multiple bonding devices, but all with the same |
00354cfb JV |
1368 | options, you may wish to use the "max_bonds" module parameter, |
1369 | documented above. | |
1da177e4 | 1370 | |
a362032e | 1371 | To create multiple bonding devices with differing options, it is |
f8b72d36 | 1372 | preferable to use bonding parameters exported by sysfs, documented in the |
9a6c6867 JV |
1373 | section below. |
1374 | ||
a362032e | 1375 | For versions of bonding without sysfs support, the only means to |
9a6c6867 JV |
1376 | provide multiple instances of bonding with differing options is to load |
1377 | the bonding driver multiple times. Note that current versions of the | |
1378 | sysconfig network initialization scripts handle this automatically; if | |
1379 | your distro uses these scripts, no special action is needed. See the | |
1380 | section Configuring Bonding Devices, above, if you're not sure about your | |
1381 | network initialization scripts. | |
1382 | ||
a362032e | 1383 | To load multiple instances of the module, it is necessary to |
9a6c6867 JV |
1384 | specify a different name for each instance (the module loading system |
1385 | requires that every loaded module, even multiple instances of the same | |
1386 | module, have a unique name). This is accomplished by supplying multiple | |
a362032e | 1387 | sets of bonding options in ``/etc/modprobe.d/*.conf``, for example:: |
9a6c6867 | 1388 | |
a362032e MCC |
1389 | alias bond0 bonding |
1390 | options bond0 -o bond0 mode=balance-rr miimon=100 | |
9a6c6867 | 1391 | |
a362032e MCC |
1392 | alias bond1 bonding |
1393 | options bond1 -o bond1 mode=balance-alb miimon=50 | |
9a6c6867 | 1394 | |
a362032e | 1395 | will load the bonding module two times. The first instance is |
9a6c6867 JV |
1396 | named "bond0" and creates the bond0 device in balance-rr mode with an |
1397 | miimon of 100. The second instance is named "bond1" and creates the | |
1398 | bond1 device in balance-alb mode with an miimon of 50. | |
1399 | ||
a362032e | 1400 | In some circumstances (typically with older distributions), |
9a6c6867 JV |
1401 | the above does not work, and the second bonding instance never sees |
1402 | its options. In that case, the second options line can be substituted | |
a362032e | 1403 | as follows:: |
9a6c6867 | 1404 | |
a362032e MCC |
1405 | install bond1 /sbin/modprobe --ignore-install bonding -o bond1 \ |
1406 | mode=balance-alb miimon=50 | |
00354cfb | 1407 | |
a362032e | 1408 | This may be repeated any number of times, specifying a new and |
9a6c6867 JV |
1409 | unique name in place of bond1 for each subsequent instance. |
1410 | ||
a362032e | 1411 | It has been observed that some Red Hat supplied kernels are unable |
9a6c6867 JV |
1412 | to rename modules at load time (the "-o bond1" part). Attempts to pass |
1413 | that option to modprobe will produce an "Operation not permitted" error. | |
1414 | This has been reported on some Fedora Core kernels, and has been seen on | |
1415 | RHEL 4 as well. On kernels exhibiting this problem, it will be impossible | |
1416 | to configure multiple bonds with differing parameters (as they are older | |
1417 | kernels, and also lack sysfs support). | |
1da177e4 | 1418 | |
6224e01d AK |
1419 | 3.4 Configuring Bonding Manually via Sysfs |
1420 | ------------------------------------------ | |
1421 | ||
a362032e | 1422 | Starting with version 3.0.0, Channel Bonding may be configured |
6224e01d AK |
1423 | via the sysfs interface. This interface allows dynamic configuration |
1424 | of all bonds in the system without unloading the module. It also | |
1425 | allows for adding and removing bonds at runtime. Ifenslave is no | |
1426 | longer required, though it is still supported. | |
1427 | ||
a362032e | 1428 | Use of the sysfs interface allows you to use multiple bonds |
6224e01d AK |
1429 | with different configurations without having to reload the module. |
1430 | It also allows you to use multiple, differently configured bonds when | |
1431 | bonding is compiled into the kernel. | |
1432 | ||
a362032e | 1433 | You must have the sysfs filesystem mounted to configure |
6224e01d AK |
1434 | bonding this way. The examples in this document assume that you |
1435 | are using the standard mount point for sysfs, e.g. /sys. If your | |
1436 | sysfs filesystem is mounted elsewhere, you will need to adjust the | |
1437 | example paths accordingly. | |
1438 | ||
1439 | Creating and Destroying Bonds | |
1440 | ----------------------------- | |
a362032e MCC |
1441 | To add a new bond foo:: |
1442 | ||
1443 | # echo +foo > /sys/class/net/bonding_masters | |
1444 | ||
1445 | To remove an existing bond bar:: | |
6224e01d | 1446 | |
a362032e | 1447 | # echo -bar > /sys/class/net/bonding_masters |
6224e01d | 1448 | |
a362032e | 1449 | To show all existing bonds:: |
6224e01d | 1450 | |
a362032e MCC |
1451 | # cat /sys/class/net/bonding_masters |
1452 | ||
1453 | .. note:: | |
1454 | ||
1455 | due to 4K size limitation of sysfs files, this list may be | |
1456 | truncated if you have more than a few hundred bonds. This is unlikely | |
1457 | to occur under normal operating conditions. | |
6224e01d AK |
1458 | |
1459 | Adding and Removing Slaves | |
1460 | -------------------------- | |
a362032e | 1461 | Interfaces may be enslaved to a bond using the file |
6224e01d AK |
1462 | /sys/class/net/<bond>/bonding/slaves. The semantics for this file |
1463 | are the same as for the bonding_masters file. | |
1464 | ||
a362032e MCC |
1465 | To enslave interface eth0 to bond bond0:: |
1466 | ||
1467 | # ifconfig bond0 up | |
1468 | # echo +eth0 > /sys/class/net/bond0/bonding/slaves | |
6224e01d | 1469 | |
a362032e | 1470 | To free slave eth0 from bond bond0:: |
6224e01d | 1471 | |
a362032e MCC |
1472 | # echo -eth0 > /sys/class/net/bond0/bonding/slaves |
1473 | ||
1474 | When an interface is enslaved to a bond, symlinks between the | |
6224e01d AK |
1475 | two are created in the sysfs filesystem. In this case, you would get |
1476 | /sys/class/net/bond0/slave_eth0 pointing to /sys/class/net/eth0, and | |
1477 | /sys/class/net/eth0/master pointing to /sys/class/net/bond0. | |
1478 | ||
a362032e | 1479 | This means that you can tell quickly whether or not an |
6224e01d AK |
1480 | interface is enslaved by looking for the master symlink. Thus: |
1481 | # echo -eth0 > /sys/class/net/eth0/master/bonding/slaves | |
1482 | will free eth0 from whatever bond it is enslaved to, regardless of | |
1483 | the name of the bond interface. | |
1484 | ||
1485 | Changing a Bond's Configuration | |
1486 | ------------------------------- | |
a362032e | 1487 | Each bond may be configured individually by manipulating the |
6224e01d AK |
1488 | files located in /sys/class/net/<bond name>/bonding |
1489 | ||
a362032e | 1490 | The names of these files correspond directly with the command- |
670e9f34 | 1491 | line parameters described elsewhere in this file, and, with the |
6224e01d AK |
1492 | exception of arp_ip_target, they accept the same values. To see the |
1493 | current setting, simply cat the appropriate file. | |
1494 | ||
a362032e | 1495 | A few examples will be given here; for specific usage |
6224e01d AK |
1496 | guidelines for each parameter, see the appropriate section in this |
1497 | document. | |
1498 | ||
a362032e MCC |
1499 | To configure bond0 for balance-alb mode:: |
1500 | ||
1501 | # ifconfig bond0 down | |
1502 | # echo 6 > /sys/class/net/bond0/bonding/mode | |
1503 | - or - | |
1504 | # echo balance-alb > /sys/class/net/bond0/bonding/mode | |
1505 | ||
1506 | .. note:: | |
1507 | ||
1508 | The bond interface must be down before the mode can be changed. | |
1509 | ||
1510 | To enable MII monitoring on bond0 with a 1 second interval:: | |
1511 | ||
1512 | # echo 1000 > /sys/class/net/bond0/bonding/miimon | |
1513 | ||
1514 | .. note:: | |
1515 | ||
1516 | If ARP monitoring is enabled, it will disabled when MII | |
1517 | monitoring is enabled, and vice-versa. | |
1518 | ||
1519 | To add ARP targets:: | |
1520 | ||
1521 | # echo +192.168.0.100 > /sys/class/net/bond0/bonding/arp_ip_target | |
1522 | # echo +192.168.0.101 > /sys/class/net/bond0/bonding/arp_ip_target | |
1523 | ||
1524 | .. note:: | |
1525 | ||
1526 | up to 16 target addresses may be specified. | |
1527 | ||
1528 | To remove an ARP target:: | |
1529 | ||
1530 | # echo -192.168.0.100 > /sys/class/net/bond0/bonding/arp_ip_target | |
1531 | ||
1532 | To configure the interval between learning packet transmits:: | |
1533 | ||
1534 | # echo 12 > /sys/class/net/bond0/bonding/lp_interval | |
1535 | ||
1536 | .. note:: | |
1537 | ||
1538 | the lp_interval is the number of seconds between instances where | |
1539 | the bonding driver sends learning packets to each slaves peer switch. The | |
1540 | default interval is 1 second. | |
7eacd038 | 1541 | |
6224e01d AK |
1542 | Example Configuration |
1543 | --------------------- | |
a362032e | 1544 | We begin with the same example that is shown in section 3.3, |
6224e01d AK |
1545 | executed with sysfs, and without using ifenslave. |
1546 | ||
a362032e | 1547 | To make a simple bond of two e100 devices (presumed to be eth0 |
6224e01d AK |
1548 | and eth1), and have it persist across reboots, edit the appropriate |
1549 | file (/etc/init.d/boot.local or /etc/rc.d/rc.local), and add the | |
a362032e | 1550 | following:: |
6224e01d | 1551 | |
a362032e MCC |
1552 | modprobe bonding |
1553 | modprobe e100 | |
1554 | echo balance-alb > /sys/class/net/bond0/bonding/mode | |
1555 | ifconfig bond0 192.168.1.1 netmask 255.255.255.0 up | |
1556 | echo 100 > /sys/class/net/bond0/bonding/miimon | |
1557 | echo +eth0 > /sys/class/net/bond0/bonding/slaves | |
1558 | echo +eth1 > /sys/class/net/bond0/bonding/slaves | |
6224e01d | 1559 | |
a362032e | 1560 | To add a second bond, with two e1000 interfaces in |
6224e01d | 1561 | active-backup mode, using ARP monitoring, add the following lines to |
a362032e | 1562 | your init script:: |
6224e01d | 1563 | |
a362032e MCC |
1564 | modprobe e1000 |
1565 | echo +bond1 > /sys/class/net/bonding_masters | |
1566 | echo active-backup > /sys/class/net/bond1/bonding/mode | |
1567 | ifconfig bond1 192.168.2.1 netmask 255.255.255.0 up | |
1568 | echo +192.168.2.100 /sys/class/net/bond1/bonding/arp_ip_target | |
1569 | echo 2000 > /sys/class/net/bond1/bonding/arp_interval | |
1570 | echo +eth2 > /sys/class/net/bond1/bonding/slaves | |
1571 | echo +eth3 > /sys/class/net/bond1/bonding/slaves | |
6224e01d | 1572 | |
de221bd5 NP |
1573 | 3.5 Configuration with Interfaces Support |
1574 | ----------------------------------------- | |
1575 | ||
a362032e | 1576 | This section applies to distros which use /etc/network/interfaces file |
de221bd5 NP |
1577 | to describe network interface configuration, most notably Debian and it's |
1578 | derivatives. | |
1579 | ||
a362032e | 1580 | The ifup and ifdown commands on Debian don't support bonding out of |
de221bd5 | 1581 | the box. The ifenslave-2.6 package should be installed to provide bonding |
a362032e MCC |
1582 | support. Once installed, this package will provide ``bond-*`` options |
1583 | to be used into /etc/network/interfaces. | |
de221bd5 | 1584 | |
a362032e | 1585 | Note that ifenslave-2.6 package will load the bonding module and use |
de221bd5 NP |
1586 | the ifenslave command when appropriate. |
1587 | ||
1588 | Example Configurations | |
1589 | ---------------------- | |
1590 | ||
1591 | In /etc/network/interfaces, the following stanza will configure bond0, in | |
a362032e | 1592 | active-backup mode, with eth0 and eth1 as slaves:: |
de221bd5 | 1593 | |
a362032e MCC |
1594 | auto bond0 |
1595 | iface bond0 inet dhcp | |
1596 | bond-slaves eth0 eth1 | |
1597 | bond-mode active-backup | |
1598 | bond-miimon 100 | |
1599 | bond-primary eth0 eth1 | |
de221bd5 NP |
1600 | |
1601 | If the above configuration doesn't work, you might have a system using | |
1602 | upstart for system startup. This is most notably true for recent | |
1603 | Ubuntu versions. The following stanza in /etc/network/interfaces will | |
a362032e MCC |
1604 | produce the same result on those systems:: |
1605 | ||
1606 | auto bond0 | |
1607 | iface bond0 inet dhcp | |
1608 | bond-slaves none | |
1609 | bond-mode active-backup | |
1610 | bond-miimon 100 | |
1611 | ||
1612 | auto eth0 | |
1613 | iface eth0 inet manual | |
1614 | bond-master bond0 | |
1615 | bond-primary eth0 eth1 | |
1616 | ||
1617 | auto eth1 | |
1618 | iface eth1 inet manual | |
1619 | bond-master bond0 | |
1620 | bond-primary eth0 eth1 | |
1621 | ||
1622 | For a full list of ``bond-*`` supported options in /etc/network/interfaces and | |
1623 | some more advanced examples tailored to you particular distros, see the files in | |
de221bd5 NP |
1624 | /usr/share/doc/ifenslave-2.6. |
1625 | ||
1626 | 3.6 Overriding Configuration for Special Cases | |
bb1d9123 | 1627 | ---------------------------------------------- |
de221bd5 | 1628 | |
bb1d9123 AG |
1629 | When using the bonding driver, the physical port which transmits a frame is |
1630 | typically selected by the bonding driver, and is not relevant to the user or | |
1631 | system administrator. The output port is simply selected using the policies of | |
1632 | the selected bonding mode. On occasion however, it is helpful to direct certain | |
1633 | classes of traffic to certain physical interfaces on output to implement | |
1634 | slightly more complex policies. For example, to reach a web server over a | |
1635 | bonded interface in which eth0 connects to a private network, while eth1 | |
1636 | connects via a public network, it may be desirous to bias the bond to send said | |
1637 | traffic over eth0 first, using eth1 only as a fall back, while all other traffic | |
1638 | can safely be sent over either interface. Such configurations may be achieved | |
1639 | using the traffic control utilities inherent in linux. | |
1640 | ||
1641 | By default the bonding driver is multiqueue aware and 16 queues are created | |
e98aa682 | 1642 | when the driver initializes (see Documentation/networking/multiqueue.rst |
bb1d9123 AG |
1643 | for details). If more or less queues are desired the module parameter |
1644 | tx_queues can be used to change this value. There is no sysfs parameter | |
1645 | available as the allocation is done at module init time. | |
1646 | ||
1647 | The output of the file /proc/net/bonding/bondX has changed so the output Queue | |
a362032e | 1648 | ID is now printed for each slave:: |
bb1d9123 | 1649 | |
a362032e MCC |
1650 | Bonding Mode: fault-tolerance (active-backup) |
1651 | Primary Slave: None | |
1652 | Currently Active Slave: eth0 | |
1653 | MII Status: up | |
1654 | MII Polling Interval (ms): 0 | |
1655 | Up Delay (ms): 0 | |
1656 | Down Delay (ms): 0 | |
bb1d9123 | 1657 | |
a362032e MCC |
1658 | Slave Interface: eth0 |
1659 | MII Status: up | |
1660 | Link Failure Count: 0 | |
1661 | Permanent HW addr: 00:1a:a0:12:8f:cb | |
1662 | Slave queue ID: 0 | |
bb1d9123 | 1663 | |
a362032e MCC |
1664 | Slave Interface: eth1 |
1665 | MII Status: up | |
1666 | Link Failure Count: 0 | |
1667 | Permanent HW addr: 00:1a:a0:12:8f:cc | |
1668 | Slave queue ID: 2 | |
bb1d9123 | 1669 | |
a362032e | 1670 | The queue_id for a slave can be set using the command:: |
bb1d9123 | 1671 | |
a362032e | 1672 | # echo "eth1:2" > /sys/class/net/bond0/bonding/queue_id |
bb1d9123 AG |
1673 | |
1674 | Any interface that needs a queue_id set should set it with multiple calls | |
1675 | like the one above until proper priorities are set for all interfaces. On | |
1676 | distributions that allow configuration via initscripts, multiple 'queue_id' | |
1677 | arguments can be added to BONDING_OPTS to set all needed slave queues. | |
1678 | ||
1679 | These queue id's can be used in conjunction with the tc utility to configure | |
1680 | a multiqueue qdisc and filters to bias certain traffic to transmit on certain | |
1681 | slave devices. For instance, say we wanted, in the above configuration to | |
1682 | force all traffic bound to 192.168.1.100 to use eth1 in the bond as its output | |
a362032e | 1683 | device. The following commands would accomplish this:: |
bb1d9123 | 1684 | |
a362032e | 1685 | # tc qdisc add dev bond0 handle 1 root multiq |
bb1d9123 | 1686 | |
a362032e MCC |
1687 | # tc filter add dev bond0 protocol ip parent 1: prio 1 u32 match ip \ |
1688 | dst 192.168.1.100 action skbedit queue_mapping 2 | |
bb1d9123 AG |
1689 | |
1690 | These commands tell the kernel to attach a multiqueue queue discipline to the | |
1691 | bond0 interface and filter traffic enqueued to it, such that packets with a dst | |
1692 | ip of 192.168.1.100 have their output queue mapping value overwritten to 2. | |
1693 | This value is then passed into the driver, causing the normal output path | |
1694 | selection policy to be overridden, selecting instead qid 2, which maps to eth1. | |
1695 | ||
1696 | Note that qid values begin at 1. Qid 0 is reserved to initiate to the driver | |
1697 | that normal output policy selection should take place. One benefit to simply | |
1698 | leaving the qid for a slave to 0 is the multiqueue awareness in the bonding | |
1699 | driver that is now present. This awareness allows tc filters to be placed on | |
1700 | slave devices as well as bond devices and the bonding driver will simply act as | |
a362032e | 1701 | a pass-through for selecting output queues on the slave device rather than |
bb1d9123 AG |
1702 | output port selection. |
1703 | ||
1704 | This feature first appeared in bonding driver version 3.7.0 and support for | |
1705 | output slave selection was limited to round-robin and active-backup modes. | |
1706 | ||
d22a5fc0 MB |
1707 | 3.7 Configuring LACP for 802.3ad mode in a more secure way |
1708 | ---------------------------------------------------------- | |
1709 | ||
1710 | When using 802.3ad bonding mode, the Actor (host) and Partner (switch) | |
1711 | exchange LACPDUs. These LACPDUs cannot be sniffed, because they are | |
1712 | destined to link local mac addresses (which switches/bridges are not | |
1713 | supposed to forward). However, most of the values are easily predictable | |
1714 | or are simply the machine's MAC address (which is trivially known to all | |
1715 | other hosts in the same L2). This implies that other machines in the L2 | |
1716 | domain can spoof LACPDU packets from other hosts to the switch and potentially | |
1717 | cause mayhem by joining (from the point of view of the switch) another | |
1718 | machine's aggregate, thus receiving a portion of that hosts incoming | |
1719 | traffic and / or spoofing traffic from that machine themselves (potentially | |
1720 | even successfully terminating some portion of flows). Though this is not | |
1721 | a likely scenario, one could avoid this possibility by simply configuring | |
1722 | few bonding parameters: | |
1723 | ||
1724 | (a) ad_actor_system : You can set a random mac-address that can be used for | |
1725 | these LACPDU exchanges. The value can not be either NULL or Multicast. | |
1726 | Also it's preferable to set the local-admin bit. Following shell code | |
a362032e | 1727 | generates a random mac-address as described above:: |
d22a5fc0 | 1728 | |
a362032e MCC |
1729 | # sys_mac_addr=$(printf '%02x:%02x:%02x:%02x:%02x:%02x' \ |
1730 | $(( (RANDOM & 0xFE) | 0x02 )) \ | |
1731 | $(( RANDOM & 0xFF )) \ | |
1732 | $(( RANDOM & 0xFF )) \ | |
1733 | $(( RANDOM & 0xFF )) \ | |
1734 | $(( RANDOM & 0xFF )) \ | |
1735 | $(( RANDOM & 0xFF ))) | |
1736 | # echo $sys_mac_addr > /sys/class/net/bond0/bonding/ad_actor_system | |
d22a5fc0 MB |
1737 | |
1738 | (b) ad_actor_sys_prio : Randomize the system priority. The default value | |
1739 | is 65535, but system can take the value from 1 - 65535. Following shell | |
a362032e | 1740 | code generates random priority and sets it:: |
d22a5fc0 | 1741 | |
a362032e MCC |
1742 | # sys_prio=$(( 1 + RANDOM + RANDOM )) |
1743 | # echo $sys_prio > /sys/class/net/bond0/bonding/ad_actor_sys_prio | |
d22a5fc0 MB |
1744 | |
1745 | (c) ad_user_port_key : Use the user portion of the port-key. The default | |
1746 | keeps this empty. These are the upper 10 bits of the port-key and value | |
1747 | ranges from 0 - 1023. Following shell code generates these 10 bits and | |
a362032e | 1748 | sets it:: |
d22a5fc0 | 1749 | |
a362032e MCC |
1750 | # usr_port_key=$(( RANDOM & 0x3FF )) |
1751 | # echo $usr_port_key > /sys/class/net/bond0/bonding/ad_user_port_key | |
d22a5fc0 MB |
1752 | |
1753 | ||
bb1d9123 | 1754 | 4 Querying Bonding Configuration |
1da177e4 LT |
1755 | ================================= |
1756 | ||
6224e01d | 1757 | 4.1 Bonding Configuration |
1da177e4 LT |
1758 | ------------------------- |
1759 | ||
a362032e | 1760 | Each bonding device has a read-only file residing in the |
1da177e4 LT |
1761 | /proc/net/bonding directory. The file contents include information |
1762 | about the bonding configuration, options and state of each slave. | |
1763 | ||
a362032e | 1764 | For example, the contents of /proc/net/bonding/bond0 after the |
1da177e4 | 1765 | driver is loaded with parameters of mode=0 and miimon=1000 is |
a362032e | 1766 | generally as follows:: |
1da177e4 LT |
1767 | |
1768 | Ethernet Channel Bonding Driver: 2.6.1 (October 29, 2004) | |
a362032e MCC |
1769 | Bonding Mode: load balancing (round-robin) |
1770 | Currently Active Slave: eth0 | |
1771 | MII Status: up | |
1772 | MII Polling Interval (ms): 1000 | |
1773 | Up Delay (ms): 0 | |
1774 | Down Delay (ms): 0 | |
1775 | ||
1776 | Slave Interface: eth1 | |
1777 | MII Status: up | |
1778 | Link Failure Count: 1 | |
1779 | ||
1780 | Slave Interface: eth0 | |
1781 | MII Status: up | |
1782 | Link Failure Count: 1 | |
1783 | ||
1784 | The precise format and contents will change depending upon the | |
1da177e4 LT |
1785 | bonding configuration, state, and version of the bonding driver. |
1786 | ||
6224e01d | 1787 | 4.2 Network configuration |
1da177e4 LT |
1788 | ------------------------- |
1789 | ||
a362032e | 1790 | The network configuration can be inspected using the ifconfig |
1da177e4 LT |
1791 | command. Bonding devices will have the MASTER flag set; Bonding slave |
1792 | devices will have the SLAVE flag set. The ifconfig output does not | |
1793 | contain information on which slaves are associated with which masters. | |
1794 | ||
a362032e | 1795 | In the example below, the bond0 interface is the master |
1da177e4 LT |
1796 | (MASTER) while eth0 and eth1 are slaves (SLAVE). Notice all slaves of |
1797 | bond0 have the same MAC address (HWaddr) as bond0 for all modes except | |
a362032e MCC |
1798 | TLB and ALB that require a unique MAC address for each slave:: |
1799 | ||
1800 | # /sbin/ifconfig | |
1801 | bond0 Link encap:Ethernet HWaddr 00:C0:F0:1F:37:B4 | |
1802 | inet addr:XXX.XXX.XXX.YYY Bcast:XXX.XXX.XXX.255 Mask:255.255.252.0 | |
1803 | UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1 | |
1804 | RX packets:7224794 errors:0 dropped:0 overruns:0 frame:0 | |
1805 | TX packets:3286647 errors:1 dropped:0 overruns:1 carrier:0 | |
1806 | collisions:0 txqueuelen:0 | |
1807 | ||
1808 | eth0 Link encap:Ethernet HWaddr 00:C0:F0:1F:37:B4 | |
1809 | UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1 | |
1810 | RX packets:3573025 errors:0 dropped:0 overruns:0 frame:0 | |
1811 | TX packets:1643167 errors:1 dropped:0 overruns:1 carrier:0 | |
1812 | collisions:0 txqueuelen:100 | |
1813 | Interrupt:10 Base address:0x1080 | |
1814 | ||
1815 | eth1 Link encap:Ethernet HWaddr 00:C0:F0:1F:37:B4 | |
1816 | UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1 | |
1817 | RX packets:3651769 errors:0 dropped:0 overruns:0 frame:0 | |
1818 | TX packets:1643480 errors:0 dropped:0 overruns:0 carrier:0 | |
1819 | collisions:0 txqueuelen:100 | |
1820 | Interrupt:9 Base address:0x1400 | |
1da177e4 | 1821 | |
6224e01d | 1822 | 5. Switch Configuration |
1da177e4 LT |
1823 | ======================= |
1824 | ||
a362032e | 1825 | For this section, "switch" refers to whatever system the |
1da177e4 LT |
1826 | bonded devices are directly connected to (i.e., where the other end of |
1827 | the cable plugs into). This may be an actual dedicated switch device, | |
1828 | or it may be another regular system (e.g., another computer running | |
1829 | Linux), | |
1830 | ||
a362032e | 1831 | The active-backup, balance-tlb and balance-alb modes do not |
1da177e4 LT |
1832 | require any specific configuration of the switch. |
1833 | ||
a362032e | 1834 | The 802.3ad mode requires that the switch have the appropriate |
1da177e4 LT |
1835 | ports configured as an 802.3ad aggregation. The precise method used |
1836 | to configure this varies from switch to switch, but, for example, a | |
1837 | Cisco 3550 series switch requires that the appropriate ports first be | |
1838 | grouped together in a single etherchannel instance, then that | |
1839 | etherchannel is set to mode "lacp" to enable 802.3ad (instead of | |
1840 | standard EtherChannel). | |
1841 | ||
a362032e | 1842 | The balance-rr, balance-xor and broadcast modes generally |
1da177e4 LT |
1843 | require that the switch have the appropriate ports grouped together. |
1844 | The nomenclature for such a group differs between switches, it may be | |
1845 | called an "etherchannel" (as in the Cisco example, above), a "trunk | |
1846 | group" or some other similar variation. For these modes, each switch | |
1847 | will also have its own configuration options for the switch's transmit | |
1848 | policy to the bond. Typical choices include XOR of either the MAC or | |
1849 | IP addresses. The transmit policy of the two peers does not need to | |
1850 | match. For these three modes, the bonding mode really selects a | |
1851 | transmit policy for an EtherChannel group; all three will interoperate | |
1852 | with another EtherChannel group. | |
1853 | ||
1854 | ||
6224e01d | 1855 | 6. 802.1q VLAN Support |
1da177e4 LT |
1856 | ====================== |
1857 | ||
a362032e | 1858 | It is possible to configure VLAN devices over a bond interface |
1da177e4 LT |
1859 | using the 8021q driver. However, only packets coming from the 8021q |
1860 | driver and passing through bonding will be tagged by default. Self | |
1861 | generated packets, for example, bonding's learning packets or ARP | |
1862 | packets generated by either ALB mode or the ARP monitor mechanism, are | |
1863 | tagged internally by bonding itself. As a result, bonding must | |
1864 | "learn" the VLAN IDs configured above it, and use those IDs to tag | |
1865 | self generated packets. | |
1866 | ||
a362032e | 1867 | For reasons of simplicity, and to support the use of adapters |
00354cfb JV |
1868 | that can do VLAN hardware acceleration offloading, the bonding |
1869 | interface declares itself as fully hardware offloading capable, it gets | |
1da177e4 LT |
1870 | the add_vid/kill_vid notifications to gather the necessary |
1871 | information, and it propagates those actions to the slaves. In case | |
1872 | of mixed adapter types, hardware accelerated tagged packets that | |
1873 | should go through an adapter that is not offloading capable are | |
1874 | "un-accelerated" by the bonding driver so the VLAN tag sits in the | |
1875 | regular location. | |
1876 | ||
a362032e | 1877 | VLAN interfaces *must* be added on top of a bonding interface |
1da177e4 LT |
1878 | only after enslaving at least one slave. The bonding interface has a |
1879 | hardware address of 00:00:00:00:00:00 until the first slave is added. | |
1880 | If the VLAN interface is created prior to the first enslavement, it | |
1881 | would pick up the all-zeroes hardware address. Once the first slave | |
1882 | is attached to the bond, the bond device itself will pick up the | |
1883 | slave's hardware address, which is then available for the VLAN device. | |
1884 | ||
a362032e | 1885 | Also, be aware that a similar problem can occur if all slaves |
1da177e4 LT |
1886 | are released from a bond that still has one or more VLAN interfaces on |
1887 | top of it. When a new slave is added, the bonding interface will | |
1888 | obtain its hardware address from the first slave, which might not | |
1889 | match the hardware address of the VLAN interfaces (which was | |
1890 | ultimately copied from an earlier slave). | |
1891 | ||
a362032e | 1892 | There are two methods to insure that the VLAN device operates |
1da177e4 LT |
1893 | with the correct hardware address if all slaves are removed from a |
1894 | bond interface: | |
1895 | ||
a362032e | 1896 | 1. Remove all VLAN interfaces then recreate them |
1da177e4 | 1897 | |
a362032e | 1898 | 2. Set the bonding interface's hardware address so that it |
1da177e4 LT |
1899 | matches the hardware address of the VLAN interfaces. |
1900 | ||
a362032e | 1901 | Note that changing a VLAN interface's HW address would set the |
00354cfb | 1902 | underlying device -- i.e. the bonding interface -- to promiscuous |
1da177e4 LT |
1903 | mode, which might not be what you want. |
1904 | ||
1905 | ||
6224e01d | 1906 | 7. Link Monitoring |
1da177e4 LT |
1907 | ================== |
1908 | ||
a362032e | 1909 | The bonding driver at present supports two schemes for |
1da177e4 LT |
1910 | monitoring a slave device's link state: the ARP monitor and the MII |
1911 | monitor. | |
1912 | ||
a362032e | 1913 | At the present time, due to implementation restrictions in the |
1da177e4 LT |
1914 | bonding driver itself, it is not possible to enable both ARP and MII |
1915 | monitoring simultaneously. | |
1916 | ||
6224e01d | 1917 | 7.1 ARP Monitor Operation |
1da177e4 LT |
1918 | ------------------------- |
1919 | ||
a362032e | 1920 | The ARP monitor operates as its name suggests: it sends ARP |
1da177e4 LT |
1921 | queries to one or more designated peer systems on the network, and |
1922 | uses the response as an indication that the link is operating. This | |
1923 | gives some assurance that traffic is actually flowing to and from one | |
1924 | or more peers on the local network. | |
1925 | ||
a362032e | 1926 | The ARP monitor relies on the device driver itself to verify |
1da177e4 | 1927 | that traffic is flowing. In particular, the driver must keep up to |
5c2a9644 FW |
1928 | date the last receive time, dev->last_rx. Drivers that use NETIF_F_LLTX |
1929 | flag must also update netdev_queue->trans_start. If they do not, then the | |
1da177e4 LT |
1930 | ARP monitor will immediately fail any slaves using that driver, and |
1931 | those slaves will stay down. If networking monitoring (tcpdump, etc) | |
1932 | shows the ARP requests and replies on the network, then it may be that | |
1933 | your device driver is not updating last_rx and trans_start. | |
1934 | ||
6224e01d | 1935 | 7.2 Configuring Multiple ARP Targets |
1da177e4 LT |
1936 | ------------------------------------ |
1937 | ||
a362032e | 1938 | While ARP monitoring can be done with just one target, it can |
1da177e4 LT |
1939 | be useful in a High Availability setup to have several targets to |
1940 | monitor. In the case of just one target, the target itself may go | |
1941 | down or have a problem making it unresponsive to ARP requests. Having | |
1942 | an additional target (or several) increases the reliability of the ARP | |
1943 | monitoring. | |
1944 | ||
a362032e | 1945 | Multiple ARP targets must be separated by commas as follows:: |
1da177e4 | 1946 | |
a362032e MCC |
1947 | # example options for ARP monitoring with three targets |
1948 | alias bond0 bonding | |
1949 | options bond0 arp_interval=60 arp_ip_target=192.168.0.1,192.168.0.3,192.168.0.9 | |
1da177e4 | 1950 | |
a362032e | 1951 | For just a single target the options would resemble:: |
1da177e4 | 1952 | |
a362032e MCC |
1953 | # example options for ARP monitoring with one target |
1954 | alias bond0 bonding | |
1955 | options bond0 arp_interval=60 arp_ip_target=192.168.0.100 | |
1da177e4 LT |
1956 | |
1957 | ||
6224e01d | 1958 | 7.3 MII Monitor Operation |
1da177e4 LT |
1959 | ------------------------- |
1960 | ||
a362032e | 1961 | The MII monitor monitors only the carrier state of the local |
1da177e4 LT |
1962 | network interface. It accomplishes this in one of three ways: by |
1963 | depending upon the device driver to maintain its carrier state, by | |
1964 | querying the device's MII registers, or by making an ethtool query to | |
1965 | the device. | |
1966 | ||
a362032e | 1967 | If the use_carrier module parameter is 1 (the default value), |
1da177e4 LT |
1968 | then the MII monitor will rely on the driver for carrier state |
1969 | information (via the netif_carrier subsystem). As explained in the | |
1970 | use_carrier parameter information, above, if the MII monitor fails to | |
1971 | detect carrier loss on the device (e.g., when the cable is physically | |
1972 | disconnected), it may be that the driver does not support | |
1973 | netif_carrier. | |
1974 | ||
a362032e | 1975 | If use_carrier is 0, then the MII monitor will first query the |
1da177e4 LT |
1976 | device's (via ioctl) MII registers and check the link state. If that |
1977 | request fails (not just that it returns carrier down), then the MII | |
1978 | monitor will make an ethtool ETHOOL_GLINK request to attempt to obtain | |
1979 | the same information. If both methods fail (i.e., the driver either | |
1980 | does not support or had some error in processing both the MII register | |
1981 | and ethtool requests), then the MII monitor will assume the link is | |
1982 | up. | |
1983 | ||
6224e01d | 1984 | 8. Potential Sources of Trouble |
1da177e4 LT |
1985 | =============================== |
1986 | ||
6224e01d | 1987 | 8.1 Adventures in Routing |
1da177e4 LT |
1988 | ------------------------- |
1989 | ||
a362032e | 1990 | When bonding is configured, it is important that the slave |
6224e01d | 1991 | devices not have routes that supersede routes of the master (or, |
1da177e4 LT |
1992 | generally, not have routes at all). For example, suppose the bonding |
1993 | device bond0 has two slaves, eth0 and eth1, and the routing table is | |
a362032e | 1994 | as follows:: |
1da177e4 | 1995 | |
a362032e MCC |
1996 | Kernel IP routing table |
1997 | Destination Gateway Genmask Flags MSS Window irtt Iface | |
1998 | 10.0.0.0 0.0.0.0 255.255.0.0 U 40 0 0 eth0 | |
1999 | 10.0.0.0 0.0.0.0 255.255.0.0 U 40 0 0 eth1 | |
2000 | 10.0.0.0 0.0.0.0 255.255.0.0 U 40 0 0 bond0 | |
2001 | 127.0.0.0 0.0.0.0 255.0.0.0 U 40 0 0 lo | |
1da177e4 | 2002 | |
a362032e | 2003 | This routing configuration will likely still update the |
1da177e4 LT |
2004 | receive/transmit times in the driver (needed by the ARP monitor), but |
2005 | may bypass the bonding driver (because outgoing traffic to, in this | |
2006 | case, another host on network 10 would use eth0 or eth1 before bond0). | |
2007 | ||
a362032e | 2008 | The ARP monitor (and ARP itself) may become confused by this |
1da177e4 LT |
2009 | configuration, because ARP requests (generated by the ARP monitor) |
2010 | will be sent on one interface (bond0), but the corresponding reply | |
2011 | will arrive on a different interface (eth0). This reply looks to ARP | |
2012 | as an unsolicited ARP reply (because ARP matches replies on an | |
2013 | interface basis), and is discarded. The MII monitor is not affected | |
2014 | by the state of the routing table. | |
2015 | ||
a362032e | 2016 | The solution here is simply to insure that slaves do not have |
1da177e4 | 2017 | routes of their own, and if for some reason they must, those routes do |
6224e01d | 2018 | not supersede routes of their master. This should generally be the |
1da177e4 LT |
2019 | case, but unusual configurations or errant manual or automatic static |
2020 | route additions may cause trouble. | |
2021 | ||
6224e01d | 2022 | 8.2 Ethernet Device Renaming |
1da177e4 LT |
2023 | ---------------------------- |
2024 | ||
a362032e | 2025 | On systems with network configuration scripts that do not |
1da177e4 LT |
2026 | associate physical devices directly with network interface names (so |
2027 | that the same physical device always has the same "ethX" name), it may | |
970e2486 LDM |
2028 | be necessary to add some special logic to config files in |
2029 | /etc/modprobe.d/. | |
1da177e4 | 2030 | |
a362032e | 2031 | For example, given a modules.conf containing the following:: |
1da177e4 | 2032 | |
a362032e MCC |
2033 | alias bond0 bonding |
2034 | options bond0 mode=some-mode miimon=50 | |
2035 | alias eth0 tg3 | |
2036 | alias eth1 tg3 | |
2037 | alias eth2 e1000 | |
2038 | alias eth3 e1000 | |
1da177e4 | 2039 | |
a362032e | 2040 | If neither eth0 and eth1 are slaves to bond0, then when the |
1da177e4 LT |
2041 | bond0 interface comes up, the devices may end up reordered. This |
2042 | happens because bonding is loaded first, then its slave device's | |
2043 | drivers are loaded next. Since no other drivers have been loaded, | |
2044 | when the e1000 driver loads, it will receive eth0 and eth1 for its | |
2045 | devices, but the bonding configuration tries to enslave eth2 and eth3 | |
2046 | (which may later be assigned to the tg3 devices). | |
2047 | ||
a362032e | 2048 | Adding the following:: |
1da177e4 | 2049 | |
a362032e | 2050 | add above bonding e1000 tg3 |
1da177e4 | 2051 | |
a362032e | 2052 | causes modprobe to load e1000 then tg3, in that order, when |
1da177e4 LT |
2053 | bonding is loaded. This command is fully documented in the |
2054 | modules.conf manual page. | |
2055 | ||
a362032e | 2056 | On systems utilizing modprobe an equivalent problem can occur. |
970e2486 | 2057 | In this case, the following can be added to config files in |
a362032e | 2058 | /etc/modprobe.d/ as:: |
1da177e4 | 2059 | |
a362032e | 2060 | softdep bonding pre: tg3 e1000 |
1da177e4 | 2061 | |
a362032e | 2062 | This will load tg3 and e1000 modules before loading the bonding one. |
970e2486 LDM |
2063 | Full documentation on this can be found in the modprobe.d and modprobe |
2064 | manual pages. | |
1da177e4 | 2065 | |
6224e01d | 2066 | 8.3. Painfully Slow Or No Failed Link Detection By Miimon |
1da177e4 LT |
2067 | --------------------------------------------------------- |
2068 | ||
a362032e | 2069 | By default, bonding enables the use_carrier option, which |
1da177e4 LT |
2070 | instructs bonding to trust the driver to maintain carrier state. |
2071 | ||
a362032e | 2072 | As discussed in the options section, above, some drivers do |
1da177e4 LT |
2073 | not support the netif_carrier_on/_off link state tracking system. |
2074 | With use_carrier enabled, bonding will always see these links as up, | |
2075 | regardless of their actual state. | |
2076 | ||
a362032e | 2077 | Additionally, other drivers do support netif_carrier, but do |
1da177e4 LT |
2078 | not maintain it in real time, e.g., only polling the link state at |
2079 | some fixed interval. In this case, miimon will detect failures, but | |
2080 | only after some long period of time has expired. If it appears that | |
2081 | miimon is very slow in detecting link failures, try specifying | |
2082 | use_carrier=0 to see if that improves the failure detection time. If | |
2083 | it does, then it may be that the driver checks the carrier state at a | |
2084 | fixed interval, but does not cache the MII register values (so the | |
2085 | use_carrier=0 method of querying the registers directly works). If | |
2086 | use_carrier=0 does not improve the failover, then the driver may cache | |
2087 | the registers, or the problem may be elsewhere. | |
2088 | ||
a362032e | 2089 | Also, remember that miimon only checks for the device's |
1da177e4 LT |
2090 | carrier state. It has no way to determine the state of devices on or |
2091 | beyond other ports of a switch, or if a switch is refusing to pass | |
2092 | traffic while still maintaining carrier on. | |
2093 | ||
6224e01d | 2094 | 9. SNMP agents |
1da177e4 LT |
2095 | =============== |
2096 | ||
a362032e | 2097 | If running SNMP agents, the bonding driver should be loaded |
1da177e4 | 2098 | before any network drivers participating in a bond. This requirement |
d533f671 | 2099 | is due to the interface index (ipAdEntIfIndex) being associated to |
1da177e4 LT |
2100 | the first interface found with a given IP address. That is, there is |
2101 | only one ipAdEntIfIndex for each IP address. For example, if eth0 and | |
2102 | eth1 are slaves of bond0 and the driver for eth0 is loaded before the | |
2103 | bonding driver, the interface for the IP address will be associated | |
2104 | with the eth0 interface. This configuration is shown below, the IP | |
2105 | address 192.168.1.1 has an interface index of 2 which indexes to eth0 | |
2106 | in the ifDescr table (ifDescr.2). | |
2107 | ||
a362032e MCC |
2108 | :: |
2109 | ||
1da177e4 LT |
2110 | interfaces.ifTable.ifEntry.ifDescr.1 = lo |
2111 | interfaces.ifTable.ifEntry.ifDescr.2 = eth0 | |
2112 | interfaces.ifTable.ifEntry.ifDescr.3 = eth1 | |
2113 | interfaces.ifTable.ifEntry.ifDescr.4 = eth2 | |
2114 | interfaces.ifTable.ifEntry.ifDescr.5 = eth3 | |
2115 | interfaces.ifTable.ifEntry.ifDescr.6 = bond0 | |
2116 | ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.10.10.10.10 = 5 | |
2117 | ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.192.168.1.1 = 2 | |
2118 | ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.10.74.20.94 = 4 | |
2119 | ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.127.0.0.1 = 1 | |
2120 | ||
a362032e | 2121 | This problem is avoided by loading the bonding driver before |
1da177e4 LT |
2122 | any network drivers participating in a bond. Below is an example of |
2123 | loading the bonding driver first, the IP address 192.168.1.1 is | |
2124 | correctly associated with ifDescr.2. | |
2125 | ||
2126 | interfaces.ifTable.ifEntry.ifDescr.1 = lo | |
2127 | interfaces.ifTable.ifEntry.ifDescr.2 = bond0 | |
2128 | interfaces.ifTable.ifEntry.ifDescr.3 = eth0 | |
2129 | interfaces.ifTable.ifEntry.ifDescr.4 = eth1 | |
2130 | interfaces.ifTable.ifEntry.ifDescr.5 = eth2 | |
2131 | interfaces.ifTable.ifEntry.ifDescr.6 = eth3 | |
2132 | ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.10.10.10.10 = 6 | |
2133 | ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.192.168.1.1 = 2 | |
2134 | ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.10.74.20.94 = 5 | |
2135 | ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.127.0.0.1 = 1 | |
2136 | ||
a362032e | 2137 | While some distributions may not report the interface name in |
1da177e4 LT |
2138 | ifDescr, the association between the IP address and IfIndex remains |
2139 | and SNMP functions such as Interface_Scan_Next will report that | |
2140 | association. | |
2141 | ||
6224e01d | 2142 | 10. Promiscuous mode |
1da177e4 LT |
2143 | ==================== |
2144 | ||
a362032e | 2145 | When running network monitoring tools, e.g., tcpdump, it is |
1da177e4 LT |
2146 | common to enable promiscuous mode on the device, so that all traffic |
2147 | is seen (instead of seeing only traffic destined for the local host). | |
2148 | The bonding driver handles promiscuous mode changes to the bonding | |
00354cfb | 2149 | master device (e.g., bond0), and propagates the setting to the slave |
1da177e4 LT |
2150 | devices. |
2151 | ||
a362032e | 2152 | For the balance-rr, balance-xor, broadcast, and 802.3ad modes, |
00354cfb | 2153 | the promiscuous mode setting is propagated to all slaves. |
1da177e4 | 2154 | |
a362032e | 2155 | For the active-backup, balance-tlb and balance-alb modes, the |
00354cfb | 2156 | promiscuous mode setting is propagated only to the active slave. |
1da177e4 | 2157 | |
a362032e | 2158 | For balance-tlb mode, the active slave is the slave currently |
1da177e4 LT |
2159 | receiving inbound traffic. |
2160 | ||
a362032e | 2161 | For balance-alb mode, the active slave is the slave used as a |
1da177e4 LT |
2162 | "primary." This slave is used for mode-specific control traffic, for |
2163 | sending to peers that are unassigned or if the load is unbalanced. | |
2164 | ||
a362032e | 2165 | For the active-backup, balance-tlb and balance-alb modes, when |
1da177e4 | 2166 | the active slave changes (e.g., due to a link failure), the |
00354cfb | 2167 | promiscuous setting will be propagated to the new active slave. |
1da177e4 | 2168 | |
6224e01d | 2169 | 11. Configuring Bonding for High Availability |
00354cfb | 2170 | ============================================= |
1da177e4 | 2171 | |
a362032e | 2172 | High Availability refers to configurations that provide |
1da177e4 | 2173 | maximum network availability by having redundant or backup devices, |
00354cfb JV |
2174 | links or switches between the host and the rest of the world. The |
2175 | goal is to provide the maximum availability of network connectivity | |
2176 | (i.e., the network always works), even though other configurations | |
2177 | could provide higher throughput. | |
1da177e4 | 2178 | |
6224e01d | 2179 | 11.1 High Availability in a Single Switch Topology |
1da177e4 LT |
2180 | -------------------------------------------------- |
2181 | ||
a362032e | 2182 | If two hosts (or a host and a single switch) are directly |
00354cfb JV |
2183 | connected via multiple physical links, then there is no availability |
2184 | penalty to optimizing for maximum bandwidth. In this case, there is | |
2185 | only one switch (or peer), so if it fails, there is no alternative | |
2186 | access to fail over to. Additionally, the bonding load balance modes | |
2187 | support link monitoring of their members, so if individual links fail, | |
2188 | the load will be rebalanced across the remaining devices. | |
2189 | ||
a362032e | 2190 | See Section 12, "Configuring Bonding for Maximum Throughput" |
00354cfb JV |
2191 | for information on configuring bonding with one peer device. |
2192 | ||
6224e01d | 2193 | 11.2 High Availability in a Multiple Switch Topology |
00354cfb JV |
2194 | ---------------------------------------------------- |
2195 | ||
a362032e | 2196 | With multiple switches, the configuration of bonding and the |
00354cfb JV |
2197 | network changes dramatically. In multiple switch topologies, there is |
2198 | a trade off between network availability and usable bandwidth. | |
2199 | ||
a362032e MCC |
2200 | Below is a sample network, configured to maximize the |
2201 | availability of the network:: | |
2202 | ||
2203 | | | | |
2204 | |port3 port3| | |
2205 | +-----+----+ +-----+----+ | |
2206 | | |port2 ISL port2| | | |
2207 | | switch A +--------------------------+ switch B | | |
2208 | | | | | | |
2209 | +-----+----+ +-----++---+ | |
2210 | |port1 port1| | |
2211 | | +-------+ | | |
2212 | +-------------+ host1 +---------------+ | |
2213 | eth0 +-------+ eth1 | |
2214 | ||
2215 | In this configuration, there is a link between the two | |
00354cfb JV |
2216 | switches (ISL, or inter switch link), and multiple ports connecting to |
2217 | the outside world ("port3" on each switch). There is no technical | |
2218 | reason that this could not be extended to a third switch. | |
1da177e4 | 2219 | |
6224e01d | 2220 | 11.2.1 HA Bonding Mode Selection for Multiple Switch Topology |
00354cfb | 2221 | ------------------------------------------------------------- |
1da177e4 | 2222 | |
a362032e | 2223 | In a topology such as the example above, the active-backup and |
00354cfb JV |
2224 | broadcast modes are the only useful bonding modes when optimizing for |
2225 | availability; the other modes require all links to terminate on the | |
2226 | same peer for them to behave rationally. | |
2227 | ||
a362032e MCC |
2228 | active-backup: |
2229 | This is generally the preferred mode, particularly if | |
00354cfb JV |
2230 | the switches have an ISL and play together well. If the |
2231 | network configuration is such that one switch is specifically | |
2232 | a backup switch (e.g., has lower capacity, higher cost, etc), | |
2233 | then the primary option can be used to insure that the | |
2234 | preferred link is always used when it is available. | |
2235 | ||
a362032e MCC |
2236 | broadcast: |
2237 | This mode is really a special purpose mode, and is suitable | |
00354cfb JV |
2238 | only for very specific needs. For example, if the two |
2239 | switches are not connected (no ISL), and the networks beyond | |
2240 | them are totally independent. In this case, if it is | |
2241 | necessary for some specific one-way traffic to reach both | |
2242 | independent networks, then the broadcast mode may be suitable. | |
2243 | ||
6224e01d | 2244 | 11.2.2 HA Link Monitoring Selection for Multiple Switch Topology |
00354cfb JV |
2245 | ---------------------------------------------------------------- |
2246 | ||
a362032e | 2247 | The choice of link monitoring ultimately depends upon your |
00354cfb JV |
2248 | switch. If the switch can reliably fail ports in response to other |
2249 | failures, then either the MII or ARP monitors should work. For | |
2250 | example, in the above example, if the "port3" link fails at the remote | |
2251 | end, the MII monitor has no direct means to detect this. The ARP | |
2252 | monitor could be configured with a target at the remote end of port3, | |
2253 | thus detecting that failure without switch support. | |
2254 | ||
a362032e | 2255 | In general, however, in a multiple switch topology, the ARP |
00354cfb JV |
2256 | monitor can provide a higher level of reliability in detecting end to |
2257 | end connectivity failures (which may be caused by the failure of any | |
2258 | individual component to pass traffic for any reason). Additionally, | |
2259 | the ARP monitor should be configured with multiple targets (at least | |
2260 | one for each switch in the network). This will insure that, | |
2261 | regardless of which switch is active, the ARP monitor has a suitable | |
2262 | target to query. | |
2263 | ||
a362032e | 2264 | Note, also, that of late many switches now support a functionality |
9a6c6867 JV |
2265 | generally referred to as "trunk failover." This is a feature of the |
2266 | switch that causes the link state of a particular switch port to be set | |
2267 | down (or up) when the state of another switch port goes down (or up). | |
19f59460 | 2268 | Its purpose is to propagate link failures from logically "exterior" ports |
9a6c6867 JV |
2269 | to the logically "interior" ports that bonding is able to monitor via |
2270 | miimon. Availability and configuration for trunk failover varies by | |
2271 | switch, but this can be a viable alternative to the ARP monitor when using | |
2272 | suitable switches. | |
00354cfb | 2273 | |
6224e01d | 2274 | 12. Configuring Bonding for Maximum Throughput |
00354cfb JV |
2275 | ============================================== |
2276 | ||
6224e01d | 2277 | 12.1 Maximizing Throughput in a Single Switch Topology |
00354cfb JV |
2278 | ------------------------------------------------------ |
2279 | ||
a362032e | 2280 | In a single switch configuration, the best method to maximize |
00354cfb JV |
2281 | throughput depends upon the application and network environment. The |
2282 | various load balancing modes each have strengths and weaknesses in | |
2283 | different environments, as detailed below. | |
2284 | ||
a362032e | 2285 | For this discussion, we will break down the topologies into |
00354cfb JV |
2286 | two categories. Depending upon the destination of most traffic, we |
2287 | categorize them into either "gatewayed" or "local" configurations. | |
2288 | ||
a362032e | 2289 | In a gatewayed configuration, the "switch" is acting primarily |
00354cfb | 2290 | as a router, and the majority of traffic passes through this router to |
a362032e | 2291 | other networks. An example would be the following:: |
00354cfb JV |
2292 | |
2293 | ||
2294 | +----------+ +----------+ | |
2295 | | |eth0 port1| | to other networks | |
2296 | | Host A +---------------------+ router +-------------------> | |
2297 | | +---------------------+ | Hosts B and C are out | |
2298 | | |eth1 port2| | here somewhere | |
2299 | +----------+ +----------+ | |
2300 | ||
a362032e | 2301 | The router may be a dedicated router device, or another host |
00354cfb JV |
2302 | acting as a gateway. For our discussion, the important point is that |
2303 | the majority of traffic from Host A will pass through the router to | |
2304 | some other network before reaching its final destination. | |
2305 | ||
a362032e | 2306 | In a gatewayed network configuration, although Host A may |
00354cfb JV |
2307 | communicate with many other systems, all of its traffic will be sent |
2308 | and received via one other peer on the local network, the router. | |
2309 | ||
a362032e | 2310 | Note that the case of two systems connected directly via |
00354cfb JV |
2311 | multiple physical links is, for purposes of configuring bonding, the |
2312 | same as a gatewayed configuration. In that case, it happens that all | |
2313 | traffic is destined for the "gateway" itself, not some other network | |
2314 | beyond the gateway. | |
2315 | ||
a362032e | 2316 | In a local configuration, the "switch" is acting primarily as |
00354cfb JV |
2317 | a switch, and the majority of traffic passes through this switch to |
2318 | reach other stations on the same network. An example would be the | |
a362032e | 2319 | following:: |
00354cfb JV |
2320 | |
2321 | +----------+ +----------+ +--------+ | |
2322 | | |eth0 port1| +-------+ Host B | | |
2323 | | Host A +------------+ switch |port3 +--------+ | |
2324 | | +------------+ | +--------+ | |
2325 | | |eth1 port2| +------------------+ Host C | | |
2326 | +----------+ +----------+port4 +--------+ | |
2327 | ||
2328 | ||
a362032e | 2329 | Again, the switch may be a dedicated switch device, or another |
00354cfb JV |
2330 | host acting as a gateway. For our discussion, the important point is |
2331 | that the majority of traffic from Host A is destined for other hosts | |
2332 | on the same local network (Hosts B and C in the above example). | |
2333 | ||
a362032e | 2334 | In summary, in a gatewayed configuration, traffic to and from |
00354cfb JV |
2335 | the bonded device will be to the same MAC level peer on the network |
2336 | (the gateway itself, i.e., the router), regardless of its final | |
2337 | destination. In a local configuration, traffic flows directly to and | |
2338 | from the final destinations, thus, each destination (Host B, Host C) | |
2339 | will be addressed directly by their individual MAC addresses. | |
2340 | ||
a362032e | 2341 | This distinction between a gatewayed and a local network |
00354cfb JV |
2342 | configuration is important because many of the load balancing modes |
2343 | available use the MAC addresses of the local network source and | |
2344 | destination to make load balancing decisions. The behavior of each | |
2345 | mode is described below. | |
2346 | ||
2347 | ||
6224e01d | 2348 | 12.1.1 MT Bonding Mode Selection for Single Switch Topology |
00354cfb | 2349 | ----------------------------------------------------------- |
1da177e4 | 2350 | |
a362032e | 2351 | This configuration is the easiest to set up and to understand, |
1da177e4 | 2352 | although you will have to decide which bonding mode best suits your |
00354cfb | 2353 | needs. The trade offs for each mode are detailed below: |
1da177e4 | 2354 | |
a362032e MCC |
2355 | balance-rr: |
2356 | This mode is the only mode that will permit a single | |
1da177e4 LT |
2357 | TCP/IP connection to stripe traffic across multiple |
2358 | interfaces. It is therefore the only mode that will allow a | |
2359 | single TCP/IP stream to utilize more than one interface's | |
2360 | worth of throughput. This comes at a cost, however: the | |
9a6c6867 | 2361 | striping generally results in peer systems receiving packets out |
1da177e4 LT |
2362 | of order, causing TCP/IP's congestion control system to kick |
2363 | in, often by retransmitting segments. | |
2364 | ||
2365 | It is possible to adjust TCP/IP's congestion limits by | |
2366 | altering the net.ipv4.tcp_reordering sysctl parameter. The | |
dca145ff ED |
2367 | usual default value is 3. But keep in mind TCP stack is able |
2368 | to automatically increase this when it detects reorders. | |
1da177e4 | 2369 | |
9a6c6867 JV |
2370 | Note that the fraction of packets that will be delivered out of |
2371 | order is highly variable, and is unlikely to be zero. The level | |
2372 | of reordering depends upon a variety of factors, including the | |
2373 | networking interfaces, the switch, and the topology of the | |
2374 | configuration. Speaking in general terms, higher speed network | |
2375 | cards produce more reordering (due to factors such as packet | |
2376 | coalescing), and a "many to many" topology will reorder at a | |
2377 | higher rate than a "many slow to one fast" configuration. | |
2378 | ||
2379 | Many switches do not support any modes that stripe traffic | |
2380 | (instead choosing a port based upon IP or MAC level addresses); | |
2381 | for those devices, traffic for a particular connection flowing | |
2382 | through the switch to a balance-rr bond will not utilize greater | |
2383 | than one interface's worth of bandwidth. | |
00354cfb | 2384 | |
1da177e4 LT |
2385 | If you are utilizing protocols other than TCP/IP, UDP for |
2386 | example, and your application can tolerate out of order | |
2387 | delivery, then this mode can allow for single stream datagram | |
2388 | performance that scales near linearly as interfaces are added | |
2389 | to the bond. | |
2390 | ||
2391 | This mode requires the switch to have the appropriate ports | |
2392 | configured for "etherchannel" or "trunking." | |
2393 | ||
a362032e MCC |
2394 | active-backup: |
2395 | There is not much advantage in this network topology to | |
1da177e4 LT |
2396 | the active-backup mode, as the inactive backup devices are all |
2397 | connected to the same peer as the primary. In this case, a | |
2398 | load balancing mode (with link monitoring) will provide the | |
2399 | same level of network availability, but with increased | |
00354cfb JV |
2400 | available bandwidth. On the plus side, active-backup mode |
2401 | does not require any configuration of the switch, so it may | |
2402 | have value if the hardware available does not support any of | |
2403 | the load balance modes. | |
1da177e4 | 2404 | |
a362032e MCC |
2405 | balance-xor: |
2406 | This mode will limit traffic such that packets destined | |
1da177e4 LT |
2407 | for specific peers will always be sent over the same |
2408 | interface. Since the destination is determined by the MAC | |
00354cfb JV |
2409 | addresses involved, this mode works best in a "local" network |
2410 | configuration (as described above), with destinations all on | |
2411 | the same local network. This mode is likely to be suboptimal | |
2412 | if all your traffic is passed through a single router (i.e., a | |
2413 | "gatewayed" network configuration, as described above). | |
2414 | ||
2415 | As with balance-rr, the switch ports need to be configured for | |
1da177e4 LT |
2416 | "etherchannel" or "trunking." |
2417 | ||
a362032e MCC |
2418 | broadcast: |
2419 | Like active-backup, there is not much advantage to this | |
1da177e4 LT |
2420 | mode in this type of network topology. |
2421 | ||
a362032e MCC |
2422 | 802.3ad: |
2423 | This mode can be a good choice for this type of network | |
1da177e4 LT |
2424 | topology. The 802.3ad mode is an IEEE standard, so all peers |
2425 | that implement 802.3ad should interoperate well. The 802.3ad | |
2426 | protocol includes automatic configuration of the aggregates, | |
2427 | so minimal manual configuration of the switch is needed | |
2428 | (typically only to designate that some set of devices is | |
00354cfb JV |
2429 | available for 802.3ad). The 802.3ad standard also mandates |
2430 | that frames be delivered in order (within certain limits), so | |
2431 | in general single connections will not see misordering of | |
1da177e4 LT |
2432 | packets. The 802.3ad mode does have some drawbacks: the |
2433 | standard mandates that all devices in the aggregate operate at | |
2434 | the same speed and duplex. Also, as with all bonding load | |
2435 | balance modes other than balance-rr, no single connection will | |
2436 | be able to utilize more than a single interface's worth of | |
a362032e | 2437 | bandwidth. |
00354cfb JV |
2438 | |
2439 | Additionally, the linux bonding 802.3ad implementation | |
92abf750 JX |
2440 | distributes traffic by peer (using an XOR of MAC addresses |
2441 | and packet type ID), so in a "gatewayed" configuration, all | |
2442 | outgoing traffic will generally use the same device. Incoming | |
2443 | traffic may also end up on a single device, but that is | |
00a534e5 | 2444 | dependent upon the balancing policy of the peer's 802.3ad |
92abf750 JX |
2445 | implementation. In a "local" configuration, traffic will be |
2446 | distributed across the devices in the bond. | |
00354cfb JV |
2447 | |
2448 | Finally, the 802.3ad mode mandates the use of the MII monitor, | |
2449 | therefore, the ARP monitor is not available in this mode. | |
2450 | ||
a362032e MCC |
2451 | balance-tlb: |
2452 | The balance-tlb mode balances outgoing traffic by peer. | |
00354cfb JV |
2453 | Since the balancing is done according to MAC address, in a |
2454 | "gatewayed" configuration (as described above), this mode will | |
2455 | send all traffic across a single device. However, in a | |
2456 | "local" network configuration, this mode balances multiple | |
2457 | local network peers across devices in a vaguely intelligent | |
2458 | manner (not a simple XOR as in balance-xor or 802.3ad mode), | |
2459 | so that mathematically unlucky MAC addresses (i.e., ones that | |
2460 | XOR to the same value) will not all "bunch up" on a single | |
2461 | interface. | |
2462 | ||
2463 | Unlike 802.3ad, interfaces may be of differing speeds, and no | |
2464 | special switch configuration is required. On the down side, | |
2465 | in this mode all incoming traffic arrives over a single | |
2466 | interface, this mode requires certain ethtool support in the | |
2467 | network device driver of the slave interfaces, and the ARP | |
2468 | monitor is not available. | |
2469 | ||
a362032e MCC |
2470 | balance-alb: |
2471 | This mode is everything that balance-tlb is, and more. | |
00354cfb JV |
2472 | It has all of the features (and restrictions) of balance-tlb, |
2473 | and will also balance incoming traffic from local network | |
2474 | peers (as described in the Bonding Module Options section, | |
2475 | above). | |
2476 | ||
2477 | The only additional down side to this mode is that the network | |
2478 | device driver must support changing the hardware address while | |
2479 | the device is open. | |
2480 | ||
6224e01d | 2481 | 12.1.2 MT Link Monitoring for Single Switch Topology |
00354cfb | 2482 | ---------------------------------------------------- |
1da177e4 | 2483 | |
a362032e | 2484 | The choice of link monitoring may largely depend upon which |
1da177e4 LT |
2485 | mode you choose to use. The more advanced load balancing modes do not |
2486 | support the use of the ARP monitor, and are thus restricted to using | |
00354cfb JV |
2487 | the MII monitor (which does not provide as high a level of end to end |
2488 | assurance as the ARP monitor). | |
2489 | ||
6224e01d | 2490 | 12.2 Maximum Throughput in a Multiple Switch Topology |
00354cfb JV |
2491 | ----------------------------------------------------- |
2492 | ||
a362032e | 2493 | Multiple switches may be utilized to optimize for throughput |
00354cfb | 2494 | when they are configured in parallel as part of an isolated network |
a362032e MCC |
2495 | between two or more systems, for example:: |
2496 | ||
2497 | +-----------+ | |
2498 | | Host A | | |
2499 | +-+---+---+-+ | |
2500 | | | | | |
2501 | +--------+ | +---------+ | |
2502 | | | | | |
2503 | +------+---+ +-----+----+ +-----+----+ | |
2504 | | Switch A | | Switch B | | Switch C | | |
2505 | +------+---+ +-----+----+ +-----+----+ | |
2506 | | | | | |
2507 | +--------+ | +---------+ | |
2508 | | | | | |
2509 | +-+---+---+-+ | |
2510 | | Host B | | |
2511 | +-----------+ | |
2512 | ||
2513 | In this configuration, the switches are isolated from one | |
00354cfb JV |
2514 | another. One reason to employ a topology such as this is for an |
2515 | isolated network with many hosts (a cluster configured for high | |
2516 | performance, for example), using multiple smaller switches can be more | |
2517 | cost effective than a single larger switch, e.g., on a network with 24 | |
2518 | hosts, three 24 port switches can be significantly less expensive than | |
2519 | a single 72 port switch. | |
2520 | ||
a362032e | 2521 | If access beyond the network is required, an individual host |
00354cfb JV |
2522 | can be equipped with an additional network device connected to an |
2523 | external network; this host then additionally acts as a gateway. | |
2524 | ||
6224e01d | 2525 | 12.2.1 MT Bonding Mode Selection for Multiple Switch Topology |
1da177e4 LT |
2526 | ------------------------------------------------------------- |
2527 | ||
a362032e | 2528 | In actual practice, the bonding mode typically employed in |
00354cfb JV |
2529 | configurations of this type is balance-rr. Historically, in this |
2530 | network configuration, the usual caveats about out of order packet | |
2531 | delivery are mitigated by the use of network adapters that do not do | |
2532 | any kind of packet coalescing (via the use of NAPI, or because the | |
2533 | device itself does not generate interrupts until some number of | |
2534 | packets has arrived). When employed in this fashion, the balance-rr | |
2535 | mode allows individual connections between two hosts to effectively | |
2536 | utilize greater than one interface's bandwidth. | |
1da177e4 | 2537 | |
6224e01d | 2538 | 12.2.2 MT Link Monitoring for Multiple Switch Topology |
00354cfb | 2539 | ------------------------------------------------------ |
1da177e4 | 2540 | |
a362032e | 2541 | Again, in actual practice, the MII monitor is most often used |
00354cfb JV |
2542 | in this configuration, as performance is given preference over |
2543 | availability. The ARP monitor will function in this topology, but its | |
2544 | advantages over the MII monitor are mitigated by the volume of probes | |
2545 | needed as the number of systems involved grows (remember that each | |
2546 | host in the network is configured with bonding). | |
1da177e4 | 2547 | |
6224e01d | 2548 | 13. Switch Behavior Issues |
00354cfb | 2549 | ========================== |
1da177e4 | 2550 | |
6224e01d | 2551 | 13.1 Link Establishment and Failover Delays |
00354cfb JV |
2552 | ------------------------------------------- |
2553 | ||
a362032e | 2554 | Some switches exhibit undesirable behavior with regard to the |
00354cfb | 2555 | timing of link up and down reporting by the switch. |
1da177e4 | 2556 | |
a362032e | 2557 | First, when a link comes up, some switches may indicate that |
1da177e4 LT |
2558 | the link is up (carrier available), but not pass traffic over the |
2559 | interface for some period of time. This delay is typically due to | |
2560 | some type of autonegotiation or routing protocol, but may also occur | |
2561 | during switch initialization (e.g., during recovery after a switch | |
2562 | failure). If you find this to be a problem, specify an appropriate | |
2563 | value to the updelay bonding module option to delay the use of the | |
2564 | relevant interface(s). | |
2565 | ||
a362032e | 2566 | Second, some switches may "bounce" the link state one or more |
1da177e4 LT |
2567 | times while a link is changing state. This occurs most commonly while |
2568 | the switch is initializing. Again, an appropriate updelay value may | |
00354cfb | 2569 | help. |
1da177e4 | 2570 | |
a362032e | 2571 | Note that when a bonding interface has no active links, the |
00354cfb JV |
2572 | driver will immediately reuse the first link that goes up, even if the |
2573 | updelay parameter has been specified (the updelay is ignored in this | |
2574 | case). If there are slave interfaces waiting for the updelay timeout | |
2575 | to expire, the interface that first went into that state will be | |
2576 | immediately reused. This reduces down time of the network if the | |
2577 | value of updelay has been overestimated, and since this occurs only in | |
2578 | cases with no connectivity, there is no additional penalty for | |
2579 | ignoring the updelay. | |
1da177e4 | 2580 | |
a362032e | 2581 | In addition to the concerns about switch timings, if your |
1da177e4 LT |
2582 | switches take a long time to go into backup mode, it may be desirable |
2583 | to not activate a backup interface immediately after a link goes down. | |
2584 | Failover may be delayed via the downdelay bonding module option. | |
2585 | ||
6224e01d | 2586 | 13.2 Duplicated Incoming Packets |
00354cfb JV |
2587 | -------------------------------- |
2588 | ||
a362032e | 2589 | NOTE: Starting with version 3.0.2, the bonding driver has logic to |
9a6c6867 JV |
2590 | suppress duplicate packets, which should largely eliminate this problem. |
2591 | The following description is kept for reference. | |
2592 | ||
a362032e | 2593 | It is not uncommon to observe a short burst of duplicated |
00354cfb JV |
2594 | traffic when the bonding device is first used, or after it has been |
2595 | idle for some period of time. This is most easily observed by issuing | |
2596 | a "ping" to some other host on the network, and noticing that the | |
2597 | output from ping flags duplicates (typically one per slave). | |
2598 | ||
a362032e MCC |
2599 | For example, on a bond in active-backup mode with five slaves |
2600 | all connected to one switch, the output may appear as follows:: | |
2601 | ||
2602 | # ping -n 10.0.4.2 | |
2603 | PING 10.0.4.2 (10.0.4.2) from 10.0.3.10 : 56(84) bytes of data. | |
2604 | 64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.7 ms | |
2605 | 64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!) | |
2606 | 64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!) | |
2607 | 64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!) | |
2608 | 64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!) | |
2609 | 64 bytes from 10.0.4.2: icmp_seq=2 ttl=64 time=0.216 ms | |
2610 | 64 bytes from 10.0.4.2: icmp_seq=3 ttl=64 time=0.267 ms | |
2611 | 64 bytes from 10.0.4.2: icmp_seq=4 ttl=64 time=0.222 ms | |
2612 | ||
2613 | This is not due to an error in the bonding driver, rather, it | |
00354cfb JV |
2614 | is a side effect of how many switches update their MAC forwarding |
2615 | tables. Initially, the switch does not associate the MAC address in | |
2616 | the packet with a particular switch port, and so it may send the | |
2617 | traffic to all ports until its MAC forwarding table is updated. Since | |
2618 | the interfaces attached to the bond may occupy multiple ports on a | |
2619 | single switch, when the switch (temporarily) floods the traffic to all | |
2620 | ports, the bond device receives multiple copies of the same packet | |
2621 | (one per slave device). | |
2622 | ||
a362032e | 2623 | The duplicated packet behavior is switch dependent, some |
00354cfb JV |
2624 | switches exhibit this, and some do not. On switches that display this |
2625 | behavior, it can be induced by clearing the MAC forwarding table (on | |
2626 | most Cisco switches, the privileged command "clear mac address-table | |
2627 | dynamic" will accomplish this). | |
2628 | ||
6224e01d | 2629 | 14. Hardware Specific Considerations |
1da177e4 LT |
2630 | ==================================== |
2631 | ||
a362032e | 2632 | This section contains additional information for configuring |
1da177e4 LT |
2633 | bonding on specific hardware platforms, or for interfacing bonding |
2634 | with particular switches or other devices. | |
2635 | ||
6224e01d | 2636 | 14.1 IBM BladeCenter |
1da177e4 LT |
2637 | -------------------- |
2638 | ||
a362032e | 2639 | This applies to the JS20 and similar systems. |
1da177e4 | 2640 | |
a362032e | 2641 | On the JS20 blades, the bonding driver supports only |
1da177e4 LT |
2642 | balance-rr, active-backup, balance-tlb and balance-alb modes. This is |
2643 | largely due to the network topology inside the BladeCenter, detailed | |
2644 | below. | |
2645 | ||
2646 | JS20 network adapter information | |
2647 | -------------------------------- | |
2648 | ||
a362032e | 2649 | All JS20s come with two Broadcom Gigabit Ethernet ports |
00354cfb JV |
2650 | integrated on the planar (that's "motherboard" in IBM-speak). In the |
2651 | BladeCenter chassis, the eth0 port of all JS20 blades is hard wired to | |
2652 | I/O Module #1; similarly, all eth1 ports are wired to I/O Module #2. | |
2653 | An add-on Broadcom daughter card can be installed on a JS20 to provide | |
2654 | two more Gigabit Ethernet ports. These ports, eth2 and eth3, are | |
2655 | wired to I/O Modules 3 and 4, respectively. | |
1da177e4 | 2656 | |
a362032e | 2657 | Each I/O Module may contain either a switch or a passthrough |
1da177e4 LT |
2658 | module (which allows ports to be directly connected to an external |
2659 | switch). Some bonding modes require a specific BladeCenter internal | |
2660 | network topology in order to function; these are detailed below. | |
2661 | ||
a362032e | 2662 | Additional BladeCenter-specific networking information can be |
1da177e4 LT |
2663 | found in two IBM Redbooks (www.ibm.com/redbooks): |
2664 | ||
a362032e MCC |
2665 | - "IBM eServer BladeCenter Networking Options" |
2666 | - "IBM eServer BladeCenter Layer 2-7 Network Switching" | |
1da177e4 LT |
2667 | |
2668 | BladeCenter networking configuration | |
2669 | ------------------------------------ | |
2670 | ||
a362032e | 2671 | Because a BladeCenter can be configured in a very large number |
1da177e4 LT |
2672 | of ways, this discussion will be confined to describing basic |
2673 | configurations. | |
2674 | ||
a362032e | 2675 | Normally, Ethernet Switch Modules (ESMs) are used in I/O |
1da177e4 LT |
2676 | modules 1 and 2. In this configuration, the eth0 and eth1 ports of a |
2677 | JS20 will be connected to different internal switches (in the | |
2678 | respective I/O modules). | |
2679 | ||
a362032e | 2680 | A passthrough module (OPM or CPM, optical or copper, |
00354cfb JV |
2681 | passthrough module) connects the I/O module directly to an external |
2682 | switch. By using PMs in I/O module #1 and #2, the eth0 and eth1 | |
2683 | interfaces of a JS20 can be redirected to the outside world and | |
2684 | connected to a common external switch. | |
2685 | ||
a362032e | 2686 | Depending upon the mix of ESMs and PMs, the network will |
00354cfb JV |
2687 | appear to bonding as either a single switch topology (all PMs) or as a |
2688 | multiple switch topology (one or more ESMs, zero or more PMs). It is | |
2689 | also possible to connect ESMs together, resulting in a configuration | |
2690 | much like the example in "High Availability in a Multiple Switch | |
2691 | Topology," above. | |
2692 | ||
2693 | Requirements for specific modes | |
2694 | ------------------------------- | |
2695 | ||
a362032e | 2696 | The balance-rr mode requires the use of passthrough modules |
00354cfb JV |
2697 | for devices in the bond, all connected to an common external switch. |
2698 | That switch must be configured for "etherchannel" or "trunking" on the | |
1da177e4 LT |
2699 | appropriate ports, as is usual for balance-rr. |
2700 | ||
a362032e | 2701 | The balance-alb and balance-tlb modes will function with |
1da177e4 LT |
2702 | either switch modules or passthrough modules (or a mix). The only |
2703 | specific requirement for these modes is that all network interfaces | |
2704 | must be able to reach all destinations for traffic sent over the | |
2705 | bonding device (i.e., the network must converge at some point outside | |
2706 | the BladeCenter). | |
2707 | ||
a362032e | 2708 | The active-backup mode has no additional requirements. |
1da177e4 LT |
2709 | |
2710 | Link monitoring issues | |
2711 | ---------------------- | |
2712 | ||
a362032e | 2713 | When an Ethernet Switch Module is in place, only the ARP |
1da177e4 LT |
2714 | monitor will reliably detect link loss to an external switch. This is |
2715 | nothing unusual, but examination of the BladeCenter cabinet would | |
2716 | suggest that the "external" network ports are the ethernet ports for | |
2717 | the system, when it fact there is a switch between these "external" | |
2718 | ports and the devices on the JS20 system itself. The MII monitor is | |
2719 | only able to detect link failures between the ESM and the JS20 system. | |
2720 | ||
a362032e | 2721 | When a passthrough module is in place, the MII monitor does |
1da177e4 LT |
2722 | detect failures to the "external" port, which is then directly |
2723 | connected to the JS20 system. | |
2724 | ||
2725 | Other concerns | |
2726 | -------------- | |
2727 | ||
a362032e | 2728 | The Serial Over LAN (SoL) link is established over the primary |
1da177e4 LT |
2729 | ethernet (eth0) only, therefore, any loss of link to eth0 will result |
2730 | in losing your SoL connection. It will not fail over with other | |
00354cfb JV |
2731 | network traffic, as the SoL system is beyond the control of the |
2732 | bonding driver. | |
1da177e4 | 2733 | |
a362032e | 2734 | It may be desirable to disable spanning tree on the switch |
1da177e4 | 2735 | (either the internal Ethernet Switch Module, or an external switch) to |
00354cfb | 2736 | avoid fail-over delay issues when using bonding. |
1da177e4 | 2737 | |
a362032e | 2738 | |
6224e01d | 2739 | 15. Frequently Asked Questions |
1da177e4 LT |
2740 | ============================== |
2741 | ||
2742 | 1. Is it SMP safe? | |
a362032e | 2743 | ------------------- |
1da177e4 | 2744 | |
a362032e | 2745 | Yes. The old 2.0.xx channel bonding patch was not SMP safe. |
1da177e4 LT |
2746 | The new driver was designed to be SMP safe from the start. |
2747 | ||
2748 | 2. What type of cards will work with it? | |
a362032e | 2749 | ----------------------------------------- |
1da177e4 | 2750 | |
a362032e | 2751 | Any Ethernet type cards (you can even mix cards - a Intel |
00354cfb JV |
2752 | EtherExpress PRO/100 and a 3com 3c905b, for example). For most modes, |
2753 | devices need not be of the same speed. | |
1da177e4 | 2754 | |
a362032e | 2755 | Starting with version 3.2.1, bonding also supports Infiniband |
9a6c6867 JV |
2756 | slaves in active-backup mode. |
2757 | ||
1da177e4 | 2758 | 3. How many bonding devices can I have? |
a362032e | 2759 | ---------------------------------------- |
1da177e4 | 2760 | |
a362032e | 2761 | There is no limit. |
1da177e4 LT |
2762 | |
2763 | 4. How many slaves can a bonding device have? | |
a362032e | 2764 | ---------------------------------------------- |
1da177e4 | 2765 | |
a362032e | 2766 | This is limited only by the number of network interfaces Linux |
1da177e4 LT |
2767 | supports and/or the number of network cards you can place in your |
2768 | system. | |
2769 | ||
2770 | 5. What happens when a slave link dies? | |
a362032e | 2771 | ---------------------------------------- |
1da177e4 | 2772 | |
a362032e | 2773 | If link monitoring is enabled, then the failing device will be |
1da177e4 LT |
2774 | disabled. The active-backup mode will fail over to a backup link, and |
2775 | other modes will ignore the failed link. The link will continue to be | |
2776 | monitored, and should it recover, it will rejoin the bond (in whatever | |
00354cfb JV |
2777 | manner is appropriate for the mode). See the sections on High |
2778 | Availability and the documentation for each mode for additional | |
2779 | information. | |
a362032e MCC |
2780 | |
2781 | Link monitoring can be enabled via either the miimon or | |
00354cfb | 2782 | arp_interval parameters (described in the module parameters section, |
1da177e4 LT |
2783 | above). In general, miimon monitors the carrier state as sensed by |
2784 | the underlying network device, and the arp monitor (arp_interval) | |
2785 | monitors connectivity to another host on the local network. | |
2786 | ||
a362032e | 2787 | If no link monitoring is configured, the bonding driver will |
1da177e4 LT |
2788 | be unable to detect link failures, and will assume that all links are |
2789 | always available. This will likely result in lost packets, and a | |
00354cfb | 2790 | resulting degradation of performance. The precise performance loss |
1da177e4 LT |
2791 | depends upon the bonding mode and network configuration. |
2792 | ||
2793 | 6. Can bonding be used for High Availability? | |
a362032e | 2794 | ---------------------------------------------- |
1da177e4 | 2795 | |
a362032e | 2796 | Yes. See the section on High Availability for details. |
1da177e4 LT |
2797 | |
2798 | 7. Which switches/systems does it work with? | |
a362032e | 2799 | --------------------------------------------- |
1da177e4 | 2800 | |
a362032e | 2801 | The full answer to this depends upon the desired mode. |
1da177e4 | 2802 | |
a362032e | 2803 | In the basic balance modes (balance-rr and balance-xor), it |
1da177e4 LT |
2804 | works with any system that supports etherchannel (also called |
2805 | trunking). Most managed switches currently available have such | |
00354cfb | 2806 | support, and many unmanaged switches as well. |
1da177e4 | 2807 | |
a362032e | 2808 | The advanced balance modes (balance-tlb and balance-alb) do |
1da177e4 LT |
2809 | not have special switch requirements, but do need device drivers that |
2810 | support specific features (described in the appropriate section under | |
00354cfb | 2811 | module parameters, above). |
1da177e4 | 2812 | |
a362032e | 2813 | In 802.3ad mode, it works with systems that support IEEE |
1da177e4 LT |
2814 | 802.3ad Dynamic Link Aggregation. Most managed and many unmanaged |
2815 | switches currently available support 802.3ad. | |
2816 | ||
a362032e | 2817 | The active-backup mode should work with any Layer-II switch. |
1da177e4 LT |
2818 | |
2819 | 8. Where does a bonding device get its MAC address from? | |
a362032e | 2820 | --------------------------------------------------------- |
1da177e4 | 2821 | |
a362032e | 2822 | When using slave devices that have fixed MAC addresses, or when |
9a6c6867 JV |
2823 | the fail_over_mac option is enabled, the bonding device's MAC address is |
2824 | the MAC address of the active slave. | |
2825 | ||
a362032e | 2826 | For other configurations, if not explicitly configured (with |
9a6c6867 JV |
2827 | ifconfig or ip link), the MAC address of the bonding device is taken from |
2828 | its first slave device. This MAC address is then passed to all following | |
2829 | slaves and remains persistent (even if the first slave is removed) until | |
2830 | the bonding device is brought down or reconfigured. | |
1da177e4 | 2831 | |
a362032e MCC |
2832 | If you wish to change the MAC address, you can set it with |
2833 | ifconfig or ip link:: | |
1da177e4 | 2834 | |
a362032e | 2835 | # ifconfig bond0 hw ether 00:11:22:33:44:55 |
1da177e4 | 2836 | |
a362032e | 2837 | # ip link set bond0 address 66:77:88:99:aa:bb |
00354cfb | 2838 | |
a362032e MCC |
2839 | The MAC address can be also changed by bringing down/up the |
2840 | device and then changing its slaves (or their order):: | |
1da177e4 | 2841 | |
a362032e MCC |
2842 | # ifconfig bond0 down ; modprobe -r bonding |
2843 | # ifconfig bond0 .... up | |
2844 | # ifenslave bond0 eth... | |
1da177e4 | 2845 | |
a362032e | 2846 | This method will automatically take the address from the next |
1da177e4 LT |
2847 | slave that is added. |
2848 | ||
a362032e MCC |
2849 | To restore your slaves' MAC addresses, you need to detach them |
2850 | from the bond (``ifenslave -d bond0 eth0``). The bonding driver will | |
1da177e4 LT |
2851 | then restore the MAC addresses that the slaves had before they were |
2852 | enslaved. | |
2853 | ||
00354cfb | 2854 | 16. Resources and Links |
1da177e4 LT |
2855 | ======================= |
2856 | ||
a362032e | 2857 | The latest version of the bonding driver can be found in the latest |
1da177e4 LT |
2858 | version of the linux kernel, found on http://kernel.org |
2859 | ||
a362032e MCC |
2860 | The latest version of this document can be found in the latest kernel |
2861 | source (named Documentation/networking/bonding.rst). | |
00354cfb | 2862 | |
a362032e | 2863 | Discussions regarding the development of the bonding driver take place |
a23c37f1 NP |
2864 | on the main Linux network mailing list, hosted at vger.kernel.org. The list |
2865 | address is: | |
2866 | ||
2867 | netdev@vger.kernel.org | |
2868 | ||
a362032e | 2869 | The administrative interface (to subscribe or unsubscribe) can |
a23c37f1 NP |
2870 | be found at: |
2871 | ||
2872 | http://vger.kernel.org/vger-lists.html#netdev |