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1 | ATA over Ethernet is a network protocol that provides simple access to |
2 | block storage on the LAN. | |
3 | ||
4 | http://support.coraid.com/documents/AoEr11.txt | |
5 | ||
eecdf226 | 6 | The EtherDrive (R) HOWTO for 2.6 and 3.x kernels is found at ... |
1da177e4 | 7 | |
eecdf226 | 8 | http://support.coraid.com/support/linux/EtherDrive-2.6-HOWTO.html |
1da177e4 | 9 | |
eecdf226 EC |
10 | It has many tips and hints! Please see, especially, recommended |
11 | tunings for virtual memory: | |
12 | ||
13 | http://support.coraid.com/support/linux/EtherDrive-2.6-HOWTO-5.html#ss5.19 | |
1da177e4 | 14 | |
67d9f847 EC |
15 | The aoetools are userland programs that are designed to work with this |
16 | driver. The aoetools are on sourceforge. | |
17 | ||
18 | http://aoetools.sourceforge.net/ | |
19 | ||
20 | The scripts in this Documentation/aoe directory are intended to | |
21 | document the use of the driver and are not necessary if you install | |
22 | the aoetools. | |
23 | ||
24 | ||
1da177e4 LT |
25 | CREATING DEVICE NODES |
26 | ||
27 | Users of udev should find the block device nodes created | |
28 | automatically, but to create all the necessary device nodes, use the | |
29 | udev configuration rules provided in udev.txt (in this directory). | |
30 | ||
31 | There is a udev-install.sh script that shows how to install these | |
32 | rules on your system. | |
33 | ||
1da177e4 | 34 | There is also an autoload script that shows how to edit |
970e2486 | 35 | /etc/modprobe.d/aoe.conf to ensure that the aoe module is loaded when |
5b8c4be3 EC |
36 | necessary. Preloading the aoe module is preferable to autoloading, |
37 | however, because AoE discovery takes a few seconds. It can be | |
38 | confusing when an AoE device is not present the first time the a | |
39 | command is run but appears a second later. | |
1da177e4 LT |
40 | |
41 | USING DEVICE NODES | |
42 | ||
43 | "cat /dev/etherd/err" blocks, waiting for error diagnostic output, | |
44 | like any retransmitted packets. | |
45 | ||
46 | "echo eth2 eth4 > /dev/etherd/interfaces" tells the aoe driver to | |
47 | limit ATA over Ethernet traffic to eth2 and eth4. AoE traffic from | |
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48 | untrusted networks should be ignored as a matter of security. See |
49 | also the aoe_iflist driver option described below. | |
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50 | |
51 | "echo > /dev/etherd/discover" tells the driver to find out what AoE | |
52 | devices are available. | |
53 | ||
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54 | In the future these character devices may disappear and be replaced |
55 | by sysfs counterparts. Using the commands in aoetools insulates | |
56 | users from these implementation details. | |
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57 | |
58 | The block devices are named like this: | |
59 | ||
60 | e{shelf}.{slot} | |
61 | e{shelf}.{slot}p{part} | |
62 | ||
63 | ... so that "e0.2" is the third blade from the left (slot 2) in the | |
64 | first shelf (shelf address zero). That's the whole disk. The first | |
65 | partition on that disk would be "e0.2p1". | |
66 | ||
67 | USING SYSFS | |
68 | ||
69 | Each aoe block device in /sys/block has the extra attributes of | |
70 | state, mac, and netif. The state attribute is "up" when the device | |
71 | is ready for I/O and "down" if detected but unusable. The | |
72 | "down,closewait" state shows that the device is still open and | |
73 | cannot come up again until it has been closed. | |
74 | ||
75 | The mac attribute is the ethernet address of the remote AoE device. | |
76 | The netif attribute is the network interface on the localhost | |
77 | through which we are communicating with the remote AoE device. | |
78 | ||
5b8c4be3 EC |
79 | There is a script in this directory that formats this information in |
80 | a convenient way. Users with aoetools should use the aoe-stat | |
67d9f847 | 81 | command. |
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82 | |
83 | root@makki root# sh Documentation/aoe/status.sh | |
84 | e10.0 eth3 up | |
85 | e10.1 eth3 up | |
86 | e10.2 eth3 up | |
87 | e10.3 eth3 up | |
88 | e10.4 eth3 up | |
89 | e10.5 eth3 up | |
90 | e10.6 eth3 up | |
91 | e10.7 eth3 up | |
92 | e10.8 eth3 up | |
93 | e10.9 eth3 up | |
94 | e4.0 eth1 up | |
95 | e4.1 eth1 up | |
96 | e4.2 eth1 up | |
97 | e4.3 eth1 up | |
98 | e4.4 eth1 up | |
99 | e4.5 eth1 up | |
100 | e4.6 eth1 up | |
101 | e4.7 eth1 up | |
102 | e4.8 eth1 up | |
103 | e4.9 eth1 up | |
03c41c43 EC |
104 | |
105 | Use /sys/module/aoe/parameters/aoe_iflist (or better, the driver | |
106 | option discussed below) instead of /dev/etherd/interfaces to limit | |
107 | AoE traffic to the network interfaces in the given | |
108 | whitespace-separated list. Unlike the old character device, the | |
109 | sysfs entry can be read from as well as written to. | |
110 | ||
111 | It's helpful to trigger discovery after setting the list of allowed | |
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112 | interfaces. The aoetools package provides an aoe-discover script |
113 | for this purpose. You can also directly use the | |
114 | /dev/etherd/discover special file described above. | |
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115 | |
116 | DRIVER OPTIONS | |
117 | ||
118 | There is a boot option for the built-in aoe driver and a | |
119 | corresponding module parameter, aoe_iflist. Without this option, | |
120 | all network interfaces may be used for ATA over Ethernet. Here is a | |
121 | usage example for the module parameter. | |
122 | ||
123 | modprobe aoe_iflist="eth1 eth3" | |
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124 | |
125 | The aoe_deadsecs module parameter determines the maximum number of | |
126 | seconds that the driver will wait for an AoE device to provide a | |
127 | response to an AoE command. After aoe_deadsecs seconds have | |
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128 | elapsed, the AoE device will be marked as "down". A value of zero |
129 | is supported for testing purposes and makes the aoe driver keep | |
130 | trying AoE commands forever. | |
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131 | |
132 | The aoe_maxout module parameter has a default of 128. This is the | |
133 | maximum number of unresponded packets that will be sent to an AoE | |
134 | target at one time. | |
135 | ||
136 | The aoe_dyndevs module parameter defaults to 1, meaning that the | |
137 | driver will assign a block device minor number to a discovered AoE | |
138 | target based on the order of its discovery. With dynamic minor | |
139 | device numbers in use, a greater range of AoE shelf and slot | |
140 | addresses can be supported. Users with udev will never have to | |
141 | think about minor numbers. Using aoe_dyndevs=0 allows device nodes | |
142 | to be pre-created using a static minor-number scheme with the | |
143 | aoe-mkshelf script in the aoetools. |