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1da177e4 LT |
1 | # |
2 | # Block device driver configuration | |
3 | # | |
4 | ||
afd44034 | 5 | menuconfig MD |
1da177e4 | 6 | bool "Multiple devices driver support (RAID and LVM)" |
afd44034 | 7 | depends on BLOCK |
1da177e4 LT |
8 | help |
9 | Support multiple physical spindles through a single logical device. | |
10 | Required for RAID and logical volume management. | |
11 | ||
afd44034 JE |
12 | if MD |
13 | ||
1da177e4 LT |
14 | config BLK_DEV_MD |
15 | tristate "RAID support" | |
1da177e4 LT |
16 | ---help--- |
17 | This driver lets you combine several hard disk partitions into one | |
18 | logical block device. This can be used to simply append one | |
19 | partition to another one or to combine several redundant hard disks | |
20 | into a RAID1/4/5 device so as to provide protection against hard | |
21 | disk failures. This is called "Software RAID" since the combining of | |
22 | the partitions is done by the kernel. "Hardware RAID" means that the | |
23 | combining is done by a dedicated controller; if you have such a | |
24 | controller, you do not need to say Y here. | |
25 | ||
26 | More information about Software RAID on Linux is contained in the | |
27 | Software RAID mini-HOWTO, available from | |
28 | <http://www.tldp.org/docs.html#howto>. There you will also learn | |
29 | where to get the supporting user space utilities raidtools. | |
30 | ||
31 | If unsure, say N. | |
32 | ||
33 | config MD_LINEAR | |
34 | tristate "Linear (append) mode" | |
35 | depends on BLK_DEV_MD | |
36 | ---help--- | |
37 | If you say Y here, then your multiple devices driver will be able to | |
38 | use the so-called linear mode, i.e. it will combine the hard disk | |
39 | partitions by simply appending one to the other. | |
40 | ||
41 | To compile this as a module, choose M here: the module | |
42 | will be called linear. | |
43 | ||
44 | If unsure, say Y. | |
45 | ||
46 | config MD_RAID0 | |
47 | tristate "RAID-0 (striping) mode" | |
48 | depends on BLK_DEV_MD | |
49 | ---help--- | |
50 | If you say Y here, then your multiple devices driver will be able to | |
51 | use the so-called raid0 mode, i.e. it will combine the hard disk | |
52 | partitions into one logical device in such a fashion as to fill them | |
53 | up evenly, one chunk here and one chunk there. This will increase | |
54 | the throughput rate if the partitions reside on distinct disks. | |
55 | ||
56 | Information about Software RAID on Linux is contained in the | |
57 | Software-RAID mini-HOWTO, available from | |
58 | <http://www.tldp.org/docs.html#howto>. There you will also | |
59 | learn where to get the supporting user space utilities raidtools. | |
60 | ||
61 | To compile this as a module, choose M here: the module | |
62 | will be called raid0. | |
63 | ||
64 | If unsure, say Y. | |
65 | ||
66 | config MD_RAID1 | |
67 | tristate "RAID-1 (mirroring) mode" | |
68 | depends on BLK_DEV_MD | |
69 | ---help--- | |
70 | A RAID-1 set consists of several disk drives which are exact copies | |
71 | of each other. In the event of a mirror failure, the RAID driver | |
72 | will continue to use the operational mirrors in the set, providing | |
73 | an error free MD (multiple device) to the higher levels of the | |
74 | kernel. In a set with N drives, the available space is the capacity | |
75 | of a single drive, and the set protects against a failure of (N - 1) | |
76 | drives. | |
77 | ||
78 | Information about Software RAID on Linux is contained in the | |
79 | Software-RAID mini-HOWTO, available from | |
80 | <http://www.tldp.org/docs.html#howto>. There you will also | |
81 | learn where to get the supporting user space utilities raidtools. | |
82 | ||
83 | If you want to use such a RAID-1 set, say Y. To compile this code | |
84 | as a module, choose M here: the module will be called raid1. | |
85 | ||
86 | If unsure, say Y. | |
87 | ||
88 | config MD_RAID10 | |
89 | tristate "RAID-10 (mirrored striping) mode (EXPERIMENTAL)" | |
90 | depends on BLK_DEV_MD && EXPERIMENTAL | |
91 | ---help--- | |
92 | RAID-10 provides a combination of striping (RAID-0) and | |
4d2554d0 | 93 | mirroring (RAID-1) with easier configuration and more flexible |
1da177e4 LT |
94 | layout. |
95 | Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to | |
96 | be the same size (or at least, only as much as the smallest device | |
97 | will be used). | |
98 | RAID-10 provides a variety of layouts that provide different levels | |
99 | of redundancy and performance. | |
100 | ||
101 | RAID-10 requires mdadm-1.7.0 or later, available at: | |
102 | ||
103 | ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/ | |
104 | ||
105 | If unsure, say Y. | |
106 | ||
16a53ecc N |
107 | config MD_RAID456 |
108 | tristate "RAID-4/RAID-5/RAID-6 mode" | |
1da177e4 | 109 | depends on BLK_DEV_MD |
9bc89cd8 DW |
110 | select ASYNC_MEMCPY |
111 | select ASYNC_XOR | |
1da177e4 LT |
112 | ---help--- |
113 | A RAID-5 set of N drives with a capacity of C MB per drive provides | |
114 | the capacity of C * (N - 1) MB, and protects against a failure | |
115 | of a single drive. For a given sector (row) number, (N - 1) drives | |
116 | contain data sectors, and one drive contains the parity protection. | |
117 | For a RAID-4 set, the parity blocks are present on a single drive, | |
118 | while a RAID-5 set distributes the parity across the drives in one | |
119 | of the available parity distribution methods. | |
120 | ||
16a53ecc N |
121 | A RAID-6 set of N drives with a capacity of C MB per drive |
122 | provides the capacity of C * (N - 2) MB, and protects | |
123 | against a failure of any two drives. For a given sector | |
124 | (row) number, (N - 2) drives contain data sectors, and two | |
125 | drives contains two independent redundancy syndromes. Like | |
126 | RAID-5, RAID-6 distributes the syndromes across the drives | |
127 | in one of the available parity distribution methods. | |
128 | ||
1da177e4 LT |
129 | Information about Software RAID on Linux is contained in the |
130 | Software-RAID mini-HOWTO, available from | |
131 | <http://www.tldp.org/docs.html#howto>. There you will also | |
132 | learn where to get the supporting user space utilities raidtools. | |
133 | ||
16a53ecc | 134 | If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To |
1da177e4 | 135 | compile this code as a module, choose M here: the module |
16a53ecc | 136 | will be called raid456. |
1da177e4 LT |
137 | |
138 | If unsure, say Y. | |
139 | ||
29269553 | 140 | config MD_RAID5_RESHAPE |
14f50b49 N |
141 | bool "Support adding drives to a raid-5 array" |
142 | depends on MD_RAID456 | |
143 | default y | |
29269553 N |
144 | ---help--- |
145 | A RAID-5 set can be expanded by adding extra drives. This | |
146 | requires "restriping" the array which means (almost) every | |
147 | block must be written to a different place. | |
148 | ||
149 | This option allows such restriping to be done while the array | |
14f50b49 | 150 | is online. |
29269553 | 151 | |
4d2554d0 | 152 | You will need mdadm version 2.4.1 or later to use this |
6f91fe88 N |
153 | feature safely. During the early stage of reshape there is |
154 | a critical section where live data is being over-written. A | |
155 | crash during this time needs extra care for recovery. The | |
156 | newer mdadm takes a copy of the data in the critical section | |
157 | and will restore it, if necessary, after a crash. | |
29269553 N |
158 | |
159 | The mdadm usage is e.g. | |
160 | mdadm --grow /dev/md1 --raid-disks=6 | |
161 | to grow '/dev/md1' to having 6 disks. | |
162 | ||
163 | Note: The array can only be expanded, not contracted. | |
164 | There should be enough spares already present to make the new | |
165 | array workable. | |
166 | ||
14f50b49 N |
167 | If unsure, say Y. |
168 | ||
1da177e4 LT |
169 | config MD_MULTIPATH |
170 | tristate "Multipath I/O support" | |
171 | depends on BLK_DEV_MD | |
172 | help | |
173 | Multipath-IO is the ability of certain devices to address the same | |
174 | physical disk over multiple 'IO paths'. The code ensures that such | |
175 | paths can be defined and handled at runtime, and ensures that a | |
176 | transparent failover to the backup path(s) happens if a IO errors | |
177 | arrives on the primary path. | |
178 | ||
179 | If unsure, say N. | |
180 | ||
181 | config MD_FAULTY | |
182 | tristate "Faulty test module for MD" | |
183 | depends on BLK_DEV_MD | |
184 | help | |
185 | The "faulty" module allows for a block device that occasionally returns | |
186 | read or write errors. It is useful for testing. | |
187 | ||
188 | In unsure, say N. | |
189 | ||
190 | config BLK_DEV_DM | |
191 | tristate "Device mapper support" | |
1da177e4 LT |
192 | ---help--- |
193 | Device-mapper is a low level volume manager. It works by allowing | |
194 | people to specify mappings for ranges of logical sectors. Various | |
195 | mapping types are available, in addition people may write their own | |
196 | modules containing custom mappings if they wish. | |
197 | ||
198 | Higher level volume managers such as LVM2 use this driver. | |
199 | ||
200 | To compile this as a module, choose M here: the module will be | |
201 | called dm-mod. | |
202 | ||
203 | If unsure, say N. | |
204 | ||
cc109201 BR |
205 | config DM_DEBUG |
206 | boolean "Device mapper debugging support" | |
207 | depends on BLK_DEV_DM && EXPERIMENTAL | |
208 | ---help--- | |
209 | Enable this for messages that may help debug device-mapper problems. | |
210 | ||
211 | If unsure, say N. | |
212 | ||
1da177e4 LT |
213 | config DM_CRYPT |
214 | tristate "Crypt target support" | |
215 | depends on BLK_DEV_DM && EXPERIMENTAL | |
216 | select CRYPTO | |
3263263f | 217 | select CRYPTO_CBC |
1da177e4 LT |
218 | ---help--- |
219 | This device-mapper target allows you to create a device that | |
220 | transparently encrypts the data on it. You'll need to activate | |
221 | the ciphers you're going to use in the cryptoapi configuration. | |
222 | ||
223 | Information on how to use dm-crypt can be found on | |
224 | ||
225 | <http://www.saout.de/misc/dm-crypt/> | |
226 | ||
227 | To compile this code as a module, choose M here: the module will | |
228 | be called dm-crypt. | |
229 | ||
230 | If unsure, say N. | |
231 | ||
232 | config DM_SNAPSHOT | |
233 | tristate "Snapshot target (EXPERIMENTAL)" | |
234 | depends on BLK_DEV_DM && EXPERIMENTAL | |
235 | ---help--- | |
4d2554d0 | 236 | Allow volume managers to take writable snapshots of a device. |
1da177e4 LT |
237 | |
238 | config DM_MIRROR | |
239 | tristate "Mirror target (EXPERIMENTAL)" | |
240 | depends on BLK_DEV_DM && EXPERIMENTAL | |
241 | ---help--- | |
242 | Allow volume managers to mirror logical volumes, also | |
243 | needed for live data migration tools such as 'pvmove'. | |
244 | ||
245 | config DM_ZERO | |
246 | tristate "Zero target (EXPERIMENTAL)" | |
247 | depends on BLK_DEV_DM && EXPERIMENTAL | |
248 | ---help--- | |
249 | A target that discards writes, and returns all zeroes for | |
250 | reads. Useful in some recovery situations. | |
251 | ||
252 | config DM_MULTIPATH | |
253 | tristate "Multipath target (EXPERIMENTAL)" | |
254 | depends on BLK_DEV_DM && EXPERIMENTAL | |
255 | ---help--- | |
256 | Allow volume managers to support multipath hardware. | |
257 | ||
258 | config DM_MULTIPATH_EMC | |
259 | tristate "EMC CX/AX multipath support (EXPERIMENTAL)" | |
260 | depends on DM_MULTIPATH && BLK_DEV_DM && EXPERIMENTAL | |
261 | ---help--- | |
262 | Multipath support for EMC CX/AX series hardware. | |
263 | ||
dd172d72 CS |
264 | config DM_MULTIPATH_RDAC |
265 | tristate "LSI/Engenio RDAC multipath support (EXPERIMENTAL)" | |
266 | depends on DM_MULTIPATH && BLK_DEV_DM && EXPERIMENTAL | |
267 | ---help--- | |
268 | Multipath support for LSI/Engenio RDAC. | |
269 | ||
26b9f228 HM |
270 | config DM_DELAY |
271 | tristate "I/O delaying target (EXPERIMENTAL)" | |
272 | depends on BLK_DEV_DM && EXPERIMENTAL | |
273 | ---help--- | |
274 | A target that delays reads and/or writes and can send | |
275 | them to different devices. Useful for testing. | |
276 | ||
277 | If unsure, say N. | |
278 | ||
afd44034 | 279 | endif # MD |