Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | # |
| 2 | # Block device driver configuration |
| 3 | # |
| 4 | |
Jan Engelhardt | afd4403 | 2007-07-17 04:06:11 -0700 | [diff] [blame] | 5 | menuconfig MD |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6 | bool "Multiple devices driver support (RAID and LVM)" |
Jan Engelhardt | afd4403 | 2007-07-17 04:06:11 -0700 | [diff] [blame] | 7 | depends on BLOCK |
Pranith Kumar | 83fe27e | 2014-12-05 11:24:45 -0500 | [diff] [blame] | 8 | select SRCU |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 9 | help |
| 10 | Support multiple physical spindles through a single logical device. |
| 11 | Required for RAID and logical volume management. |
| 12 | |
Jan Engelhardt | afd4403 | 2007-07-17 04:06:11 -0700 | [diff] [blame] | 13 | if MD |
| 14 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | config BLK_DEV_MD |
| 16 | tristate "RAID support" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | ---help--- |
| 18 | This driver lets you combine several hard disk partitions into one |
| 19 | logical block device. This can be used to simply append one |
| 20 | partition to another one or to combine several redundant hard disks |
| 21 | into a RAID1/4/5 device so as to provide protection against hard |
| 22 | disk failures. This is called "Software RAID" since the combining of |
| 23 | the partitions is done by the kernel. "Hardware RAID" means that the |
| 24 | combining is done by a dedicated controller; if you have such a |
| 25 | controller, you do not need to say Y here. |
| 26 | |
| 27 | More information about Software RAID on Linux is contained in the |
| 28 | Software RAID mini-HOWTO, available from |
| 29 | <http://www.tldp.org/docs.html#howto>. There you will also learn |
| 30 | where to get the supporting user space utilities raidtools. |
| 31 | |
| 32 | If unsure, say N. |
| 33 | |
Arjan van de Ven | a364092 | 2008-09-21 15:44:32 -0700 | [diff] [blame] | 34 | config MD_AUTODETECT |
| 35 | bool "Autodetect RAID arrays during kernel boot" |
Alan Jenkins | ce52aeb | 2008-10-10 16:02:53 +0100 | [diff] [blame] | 36 | depends on BLK_DEV_MD=y |
Arjan van de Ven | a364092 | 2008-09-21 15:44:32 -0700 | [diff] [blame] | 37 | default y |
| 38 | ---help--- |
| 39 | If you say Y here, then the kernel will try to autodetect raid |
| 40 | arrays as part of its boot process. |
| 41 | |
| 42 | If you don't use raid and say Y, this autodetection can cause |
| 43 | a several-second delay in the boot time due to various |
| 44 | synchronisation steps that are part of this step. |
| 45 | |
| 46 | If unsure, say Y. |
| 47 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | config MD_LINEAR |
| 49 | tristate "Linear (append) mode" |
| 50 | depends on BLK_DEV_MD |
| 51 | ---help--- |
| 52 | If you say Y here, then your multiple devices driver will be able to |
| 53 | use the so-called linear mode, i.e. it will combine the hard disk |
| 54 | partitions by simply appending one to the other. |
| 55 | |
| 56 | To compile this as a module, choose M here: the module |
| 57 | will be called linear. |
| 58 | |
| 59 | If unsure, say Y. |
| 60 | |
| 61 | config MD_RAID0 |
| 62 | tristate "RAID-0 (striping) mode" |
| 63 | depends on BLK_DEV_MD |
| 64 | ---help--- |
| 65 | If you say Y here, then your multiple devices driver will be able to |
| 66 | use the so-called raid0 mode, i.e. it will combine the hard disk |
| 67 | partitions into one logical device in such a fashion as to fill them |
| 68 | up evenly, one chunk here and one chunk there. This will increase |
| 69 | the throughput rate if the partitions reside on distinct disks. |
| 70 | |
| 71 | Information about Software RAID on Linux is contained in the |
| 72 | Software-RAID mini-HOWTO, available from |
| 73 | <http://www.tldp.org/docs.html#howto>. There you will also |
| 74 | learn where to get the supporting user space utilities raidtools. |
| 75 | |
| 76 | To compile this as a module, choose M here: the module |
| 77 | will be called raid0. |
| 78 | |
| 79 | If unsure, say Y. |
| 80 | |
| 81 | config MD_RAID1 |
| 82 | tristate "RAID-1 (mirroring) mode" |
| 83 | depends on BLK_DEV_MD |
| 84 | ---help--- |
| 85 | A RAID-1 set consists of several disk drives which are exact copies |
| 86 | of each other. In the event of a mirror failure, the RAID driver |
| 87 | will continue to use the operational mirrors in the set, providing |
| 88 | an error free MD (multiple device) to the higher levels of the |
| 89 | kernel. In a set with N drives, the available space is the capacity |
| 90 | of a single drive, and the set protects against a failure of (N - 1) |
| 91 | drives. |
| 92 | |
| 93 | Information about Software RAID on Linux is contained in the |
| 94 | Software-RAID mini-HOWTO, available from |
| 95 | <http://www.tldp.org/docs.html#howto>. There you will also |
| 96 | learn where to get the supporting user space utilities raidtools. |
| 97 | |
| 98 | If you want to use such a RAID-1 set, say Y. To compile this code |
| 99 | as a module, choose M here: the module will be called raid1. |
| 100 | |
| 101 | If unsure, say Y. |
| 102 | |
| 103 | config MD_RAID10 |
NeilBrown | 08fb730 | 2010-05-03 13:16:56 +1000 | [diff] [blame] | 104 | tristate "RAID-10 (mirrored striping) mode" |
| 105 | depends on BLK_DEV_MD |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | ---help--- |
| 107 | RAID-10 provides a combination of striping (RAID-0) and |
Justin Piszcz | 4d2554d | 2006-06-26 00:27:50 -0700 | [diff] [blame] | 108 | mirroring (RAID-1) with easier configuration and more flexible |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 109 | layout. |
| 110 | Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to |
| 111 | be the same size (or at least, only as much as the smallest device |
| 112 | will be used). |
| 113 | RAID-10 provides a variety of layouts that provide different levels |
| 114 | of redundancy and performance. |
| 115 | |
| 116 | RAID-10 requires mdadm-1.7.0 or later, available at: |
| 117 | |
| 118 | ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/ |
| 119 | |
| 120 | If unsure, say Y. |
| 121 | |
NeilBrown | 16a53ec | 2006-06-26 00:27:38 -0700 | [diff] [blame] | 122 | config MD_RAID456 |
| 123 | tristate "RAID-4/RAID-5/RAID-6 mode" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | depends on BLK_DEV_MD |
David Woodhouse | f5e70d0 | 2009-07-13 11:35:12 +0100 | [diff] [blame] | 125 | select RAID6_PQ |
Dan Williams | 9bc89cd | 2007-01-02 11:10:44 -0700 | [diff] [blame] | 126 | select ASYNC_MEMCPY |
| 127 | select ASYNC_XOR |
Dan Williams | ac6b53b | 2009-07-14 13:40:19 -0700 | [diff] [blame] | 128 | select ASYNC_PQ |
| 129 | select ASYNC_RAID6_RECOV |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | ---help--- |
| 131 | A RAID-5 set of N drives with a capacity of C MB per drive provides |
| 132 | the capacity of C * (N - 1) MB, and protects against a failure |
| 133 | of a single drive. For a given sector (row) number, (N - 1) drives |
| 134 | contain data sectors, and one drive contains the parity protection. |
| 135 | For a RAID-4 set, the parity blocks are present on a single drive, |
| 136 | while a RAID-5 set distributes the parity across the drives in one |
| 137 | of the available parity distribution methods. |
| 138 | |
NeilBrown | 16a53ec | 2006-06-26 00:27:38 -0700 | [diff] [blame] | 139 | A RAID-6 set of N drives with a capacity of C MB per drive |
| 140 | provides the capacity of C * (N - 2) MB, and protects |
| 141 | against a failure of any two drives. For a given sector |
| 142 | (row) number, (N - 2) drives contain data sectors, and two |
| 143 | drives contains two independent redundancy syndromes. Like |
| 144 | RAID-5, RAID-6 distributes the syndromes across the drives |
| 145 | in one of the available parity distribution methods. |
| 146 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 147 | Information about Software RAID on Linux is contained in the |
| 148 | Software-RAID mini-HOWTO, available from |
| 149 | <http://www.tldp.org/docs.html#howto>. There you will also |
| 150 | learn where to get the supporting user space utilities raidtools. |
| 151 | |
NeilBrown | 16a53ec | 2006-06-26 00:27:38 -0700 | [diff] [blame] | 152 | If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 153 | compile this code as a module, choose M here: the module |
NeilBrown | 16a53ec | 2006-06-26 00:27:38 -0700 | [diff] [blame] | 154 | will be called raid456. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 155 | |
| 156 | If unsure, say Y. |
| 157 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | config MD_MULTIPATH |
| 159 | tristate "Multipath I/O support" |
| 160 | depends on BLK_DEV_MD |
| 161 | help |
NeilBrown | 93bd89a6 | 2009-12-14 12:49:59 +1100 | [diff] [blame] | 162 | MD_MULTIPATH provides a simple multi-path personality for use |
| 163 | the MD framework. It is not under active development. New |
| 164 | projects should consider using DM_MULTIPATH which has more |
| 165 | features and more testing. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | |
| 167 | If unsure, say N. |
| 168 | |
| 169 | config MD_FAULTY |
| 170 | tristate "Faulty test module for MD" |
| 171 | depends on BLK_DEV_MD |
| 172 | help |
| 173 | The "faulty" module allows for a block device that occasionally returns |
| 174 | read or write errors. It is useful for testing. |
| 175 | |
| 176 | In unsure, say N. |
| 177 | |
Goldwyn Rodrigues | 8e854e9 | 2014-03-07 11:21:15 -0600 | [diff] [blame] | 178 | |
| 179 | config MD_CLUSTER |
| 180 | tristate "Cluster Support for MD (EXPERIMENTAL)" |
| 181 | depends on BLK_DEV_MD |
| 182 | depends on DLM |
| 183 | default n |
| 184 | ---help--- |
| 185 | Clustering support for MD devices. This enables locking and |
| 186 | synchronization across multiple systems on the cluster, so all |
| 187 | nodes in the cluster can access the MD devices simultaneously. |
| 188 | |
| 189 | This brings the redundancy (and uptime) of RAID levels across the |
| 190 | nodes of the cluster. |
| 191 | |
| 192 | If unsure, say N. |
| 193 | |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 194 | source "drivers/md/bcache/Kconfig" |
| 195 | |
Mikulas Patocka | 2995fa7 | 2014-01-13 19:37:54 -0500 | [diff] [blame] | 196 | config BLK_DEV_DM_BUILTIN |
Christoph Jaeger | 6341e62 | 2014-12-20 15:41:11 -0500 | [diff] [blame] | 197 | bool |
Mikulas Patocka | 2995fa7 | 2014-01-13 19:37:54 -0500 | [diff] [blame] | 198 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | config BLK_DEV_DM |
| 200 | tristate "Device mapper support" |
Mikulas Patocka | 2995fa7 | 2014-01-13 19:37:54 -0500 | [diff] [blame] | 201 | select BLK_DEV_DM_BUILTIN |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | ---help--- |
| 203 | Device-mapper is a low level volume manager. It works by allowing |
| 204 | people to specify mappings for ranges of logical sectors. Various |
| 205 | mapping types are available, in addition people may write their own |
| 206 | modules containing custom mappings if they wish. |
| 207 | |
| 208 | Higher level volume managers such as LVM2 use this driver. |
| 209 | |
| 210 | To compile this as a module, choose M here: the module will be |
| 211 | called dm-mod. |
| 212 | |
| 213 | If unsure, say N. |
| 214 | |
Mike Snitzer | 17e149b | 2015-03-11 15:01:09 -0400 | [diff] [blame] | 215 | config DM_MQ_DEFAULT |
| 216 | bool "request-based DM: use blk-mq I/O path by default" |
| 217 | depends on BLK_DEV_DM |
| 218 | ---help--- |
| 219 | This option enables the blk-mq based I/O path for request-based |
| 220 | DM devices by default. With the option the dm_mod.use_blk_mq |
| 221 | module/boot option defaults to Y, without it to N, but it can |
| 222 | still be overriden either way. |
| 223 | |
| 224 | If unsure say N. |
| 225 | |
Bryn Reeves | cc10920 | 2006-10-03 01:15:35 -0700 | [diff] [blame] | 226 | config DM_DEBUG |
Christoph Jaeger | 6341e62 | 2014-12-20 15:41:11 -0500 | [diff] [blame] | 227 | bool "Device mapper debugging support" |
Alasdair G Kergon | 0149e57 | 2008-02-08 02:10:32 +0000 | [diff] [blame] | 228 | depends on BLK_DEV_DM |
Bryn Reeves | cc10920 | 2006-10-03 01:15:35 -0700 | [diff] [blame] | 229 | ---help--- |
| 230 | Enable this for messages that may help debug device-mapper problems. |
| 231 | |
| 232 | If unsure, say N. |
| 233 | |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 234 | config DM_BUFIO |
| 235 | tristate |
Alasdair G Kergon | d57916a | 2013-03-01 22:45:46 +0000 | [diff] [blame] | 236 | depends on BLK_DEV_DM |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 237 | ---help--- |
| 238 | This interface allows you to do buffered I/O on a device and acts |
| 239 | as a cache, holding recently-read blocks in memory and performing |
| 240 | delayed writes. |
| 241 | |
Mike Snitzer | 4f81a41 | 2012-10-12 21:02:13 +0100 | [diff] [blame] | 242 | config DM_BIO_PRISON |
| 243 | tristate |
Alasdair G Kergon | d57916a | 2013-03-01 22:45:46 +0000 | [diff] [blame] | 244 | depends on BLK_DEV_DM |
Mike Snitzer | 4f81a41 | 2012-10-12 21:02:13 +0100 | [diff] [blame] | 245 | ---help--- |
| 246 | Some bio locking schemes used by other device-mapper targets |
| 247 | including thin provisioning. |
| 248 | |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 249 | source "drivers/md/persistent-data/Kconfig" |
| 250 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 251 | config DM_CRYPT |
| 252 | tristate "Crypt target support" |
Alasdair G Kergon | 0149e57 | 2008-02-08 02:10:32 +0000 | [diff] [blame] | 253 | depends on BLK_DEV_DM |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 254 | select CRYPTO |
Herbert Xu | 3263263 | 2006-12-10 09:50:36 +1100 | [diff] [blame] | 255 | select CRYPTO_CBC |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 256 | ---help--- |
| 257 | This device-mapper target allows you to create a device that |
| 258 | transparently encrypts the data on it. You'll need to activate |
| 259 | the ciphers you're going to use in the cryptoapi configuration. |
| 260 | |
Loic Pefferkorn | cf35248 | 2014-12-15 22:18:43 +0100 | [diff] [blame] | 261 | For further information on dm-crypt and userspace tools see: |
| 262 | <http://code.google.com/p/cryptsetup/wiki/DMCrypt> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 263 | |
| 264 | To compile this code as a module, choose M here: the module will |
| 265 | be called dm-crypt. |
| 266 | |
| 267 | If unsure, say N. |
| 268 | |
| 269 | config DM_SNAPSHOT |
Alasdair G Kergon | 0149e57 | 2008-02-08 02:10:32 +0000 | [diff] [blame] | 270 | tristate "Snapshot target" |
| 271 | depends on BLK_DEV_DM |
Mikulas Patocka | 55494bf | 2014-01-13 19:12:36 -0500 | [diff] [blame] | 272 | select DM_BUFIO |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 273 | ---help--- |
Justin Piszcz | 4d2554d | 2006-06-26 00:27:50 -0700 | [diff] [blame] | 274 | Allow volume managers to take writable snapshots of a device. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 275 | |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 276 | config DM_THIN_PROVISIONING |
Alasdair G Kergon | d57916a | 2013-03-01 22:45:46 +0000 | [diff] [blame] | 277 | tristate "Thin provisioning target" |
| 278 | depends on BLK_DEV_DM |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 279 | select DM_PERSISTENT_DATA |
Mike Snitzer | 4f81a41 | 2012-10-12 21:02:13 +0100 | [diff] [blame] | 280 | select DM_BIO_PRISON |
Joe Thornber | 991d9fa | 2011-10-31 20:21:18 +0000 | [diff] [blame] | 281 | ---help--- |
| 282 | Provides thin provisioning and snapshots that share a data store. |
| 283 | |
Joe Thornber | c6b4fcb | 2013-03-01 22:45:51 +0000 | [diff] [blame] | 284 | config DM_CACHE |
| 285 | tristate "Cache target (EXPERIMENTAL)" |
| 286 | depends on BLK_DEV_DM |
| 287 | default n |
| 288 | select DM_PERSISTENT_DATA |
| 289 | select DM_BIO_PRISON |
| 290 | ---help--- |
| 291 | dm-cache attempts to improve performance of a block device by |
| 292 | moving frequently used data to a smaller, higher performance |
| 293 | device. Different 'policy' plugins can be used to change the |
| 294 | algorithms used to select which blocks are promoted, demoted, |
| 295 | cleaned etc. It supports writeback and writethrough modes. |
| 296 | |
Joe Thornber | f283635 | 2013-03-01 22:45:51 +0000 | [diff] [blame] | 297 | config DM_CACHE_MQ |
| 298 | tristate "MQ Cache Policy (EXPERIMENTAL)" |
| 299 | depends on DM_CACHE |
| 300 | default y |
| 301 | ---help--- |
| 302 | A cache policy that uses a multiqueue ordered by recent hit |
| 303 | count to select which blocks should be promoted and demoted. |
| 304 | This is meant to be a general purpose policy. It prioritises |
| 305 | reads over writes. |
| 306 | |
Heinz Mauelshagen | 8735a81 | 2013-03-01 22:45:52 +0000 | [diff] [blame] | 307 | config DM_CACHE_CLEANER |
| 308 | tristate "Cleaner Cache Policy (EXPERIMENTAL)" |
| 309 | depends on DM_CACHE |
| 310 | default y |
| 311 | ---help--- |
| 312 | A simple cache policy that writes back all data to the |
| 313 | origin. Used when decommissioning a dm-cache. |
| 314 | |
Joe Thornber | eec4057 | 2014-03-03 10:23:15 -0500 | [diff] [blame] | 315 | config DM_ERA |
| 316 | tristate "Era target (EXPERIMENTAL)" |
| 317 | depends on BLK_DEV_DM |
| 318 | default n |
| 319 | select DM_PERSISTENT_DATA |
| 320 | select DM_BIO_PRISON |
| 321 | ---help--- |
| 322 | dm-era tracks which parts of a block device are written to |
| 323 | over time. Useful for maintaining cache coherency when using |
| 324 | vendor snapshots. |
| 325 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 326 | config DM_MIRROR |
Alasdair G Kergon | 0149e57 | 2008-02-08 02:10:32 +0000 | [diff] [blame] | 327 | tristate "Mirror target" |
| 328 | depends on BLK_DEV_DM |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 329 | ---help--- |
| 330 | Allow volume managers to mirror logical volumes, also |
| 331 | needed for live data migration tools such as 'pvmove'. |
| 332 | |
Mikulas Patocka | 5442851 | 2013-11-08 10:47:12 -0500 | [diff] [blame] | 333 | config DM_LOG_USERSPACE |
| 334 | tristate "Mirror userspace logging" |
| 335 | depends on DM_MIRROR && NET |
| 336 | select CONNECTOR |
| 337 | ---help--- |
| 338 | The userspace logging module provides a mechanism for |
| 339 | relaying the dm-dirty-log API to userspace. Log designs |
| 340 | which are more suited to userspace implementation (e.g. |
| 341 | shared storage logs) or experimental logs can be implemented |
| 342 | by leveraging this framework. |
| 343 | |
NeilBrown | 9d09e66 | 2011-01-13 20:00:02 +0000 | [diff] [blame] | 344 | config DM_RAID |
NeilBrown | d9f691c | 2012-08-02 08:35:43 +1000 | [diff] [blame] | 345 | tristate "RAID 1/4/5/6/10 target" |
Alasdair G Kergon | 035220b | 2012-03-28 18:41:24 +0100 | [diff] [blame] | 346 | depends on BLK_DEV_DM |
Jonathan Brassow | b12d437 | 2011-08-02 12:32:07 +0100 | [diff] [blame] | 347 | select MD_RAID1 |
NeilBrown | d9f691c | 2012-08-02 08:35:43 +1000 | [diff] [blame] | 348 | select MD_RAID10 |
NeilBrown | 9d09e66 | 2011-01-13 20:00:02 +0000 | [diff] [blame] | 349 | select MD_RAID456 |
| 350 | select BLK_DEV_MD |
| 351 | ---help--- |
NeilBrown | d9f691c | 2012-08-02 08:35:43 +1000 | [diff] [blame] | 352 | A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings |
NeilBrown | 9d09e66 | 2011-01-13 20:00:02 +0000 | [diff] [blame] | 353 | |
| 354 | A RAID-5 set of N drives with a capacity of C MB per drive provides |
| 355 | the capacity of C * (N - 1) MB, and protects against a failure |
| 356 | of a single drive. For a given sector (row) number, (N - 1) drives |
| 357 | contain data sectors, and one drive contains the parity protection. |
| 358 | For a RAID-4 set, the parity blocks are present on a single drive, |
| 359 | while a RAID-5 set distributes the parity across the drives in one |
| 360 | of the available parity distribution methods. |
| 361 | |
| 362 | A RAID-6 set of N drives with a capacity of C MB per drive |
| 363 | provides the capacity of C * (N - 2) MB, and protects |
| 364 | against a failure of any two drives. For a given sector |
| 365 | (row) number, (N - 2) drives contain data sectors, and two |
| 366 | drives contains two independent redundancy syndromes. Like |
| 367 | RAID-5, RAID-6 distributes the syndromes across the drives |
| 368 | in one of the available parity distribution methods. |
| 369 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 370 | config DM_ZERO |
Alasdair G Kergon | 0149e57 | 2008-02-08 02:10:32 +0000 | [diff] [blame] | 371 | tristate "Zero target" |
| 372 | depends on BLK_DEV_DM |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 373 | ---help--- |
| 374 | A target that discards writes, and returns all zeroes for |
| 375 | reads. Useful in some recovery situations. |
| 376 | |
| 377 | config DM_MULTIPATH |
Alasdair G Kergon | 0149e57 | 2008-02-08 02:10:32 +0000 | [diff] [blame] | 378 | tristate "Multipath target" |
| 379 | depends on BLK_DEV_DM |
Chandra Seetharaman | fe9233f | 2008-05-23 18:16:40 -0700 | [diff] [blame] | 380 | # nasty syntax but means make DM_MULTIPATH independent |
| 381 | # of SCSI_DH if the latter isn't defined but if |
| 382 | # it is, DM_MULTIPATH must depend on it. We get a build |
| 383 | # error if SCSI_DH=m and DM_MULTIPATH=y |
| 384 | depends on SCSI_DH || !SCSI_DH |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 385 | ---help--- |
| 386 | Allow volume managers to support multipath hardware. |
| 387 | |
Kiyoshi Ueda | fd5e033 | 2009-06-22 10:12:27 +0100 | [diff] [blame] | 388 | config DM_MULTIPATH_QL |
| 389 | tristate "I/O Path Selector based on the number of in-flight I/Os" |
| 390 | depends on DM_MULTIPATH |
| 391 | ---help--- |
| 392 | This path selector is a dynamic load balancer which selects |
| 393 | the path with the least number of in-flight I/Os. |
| 394 | |
| 395 | If unsure, say N. |
| 396 | |
Kiyoshi Ueda | f392ba8 | 2009-06-22 10:12:28 +0100 | [diff] [blame] | 397 | config DM_MULTIPATH_ST |
| 398 | tristate "I/O Path Selector based on the service time" |
| 399 | depends on DM_MULTIPATH |
| 400 | ---help--- |
| 401 | This path selector is a dynamic load balancer which selects |
| 402 | the path expected to complete the incoming I/O in the shortest |
| 403 | time. |
| 404 | |
| 405 | If unsure, say N. |
| 406 | |
Heinz Mauelshagen | 26b9f22 | 2007-05-09 02:33:06 -0700 | [diff] [blame] | 407 | config DM_DELAY |
Alasdair G Kergon | d57916a | 2013-03-01 22:45:46 +0000 | [diff] [blame] | 408 | tristate "I/O delaying target" |
| 409 | depends on BLK_DEV_DM |
Heinz Mauelshagen | 26b9f22 | 2007-05-09 02:33:06 -0700 | [diff] [blame] | 410 | ---help--- |
| 411 | A target that delays reads and/or writes and can send |
| 412 | them to different devices. Useful for testing. |
| 413 | |
| 414 | If unsure, say N. |
| 415 | |
Mike Anderson | 51e5b2b | 2007-10-19 22:48:00 +0100 | [diff] [blame] | 416 | config DM_UEVENT |
Alasdair G Kergon | e0b215d | 2012-03-28 18:41:24 +0100 | [diff] [blame] | 417 | bool "DM uevents" |
| 418 | depends on BLK_DEV_DM |
Mike Anderson | 51e5b2b | 2007-10-19 22:48:00 +0100 | [diff] [blame] | 419 | ---help--- |
| 420 | Generate udev events for DM events. |
| 421 | |
Josef Bacik | 3407ef5 | 2011-03-24 13:54:24 +0000 | [diff] [blame] | 422 | config DM_FLAKEY |
Alasdair G Kergon | d57916a | 2013-03-01 22:45:46 +0000 | [diff] [blame] | 423 | tristate "Flakey target" |
| 424 | depends on BLK_DEV_DM |
Josef Bacik | 3407ef5 | 2011-03-24 13:54:24 +0000 | [diff] [blame] | 425 | ---help--- |
| 426 | A target that intermittently fails I/O for debugging purposes. |
| 427 | |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 428 | config DM_VERITY |
Alasdair G Kergon | d57916a | 2013-03-01 22:45:46 +0000 | [diff] [blame] | 429 | tristate "Verity target support" |
| 430 | depends on BLK_DEV_DM |
Mikulas Patocka | a4ffc15 | 2012-03-28 18:43:38 +0100 | [diff] [blame] | 431 | select CRYPTO |
| 432 | select CRYPTO_HASH |
| 433 | select DM_BUFIO |
| 434 | ---help--- |
| 435 | This device-mapper target creates a read-only device that |
| 436 | transparently validates the data on one underlying device against |
| 437 | a pre-generated tree of cryptographic checksums stored on a second |
| 438 | device. |
| 439 | |
| 440 | You'll need to activate the digests you're going to use in the |
| 441 | cryptoapi configuration. |
| 442 | |
| 443 | To compile this code as a module, choose M here: the module will |
| 444 | be called dm-verity. |
| 445 | |
| 446 | If unsure, say N. |
| 447 | |
Jim Ramsay | 9d0eb0a | 2013-07-10 23:41:19 +0100 | [diff] [blame] | 448 | config DM_SWITCH |
| 449 | tristate "Switch target support (EXPERIMENTAL)" |
| 450 | depends on BLK_DEV_DM |
| 451 | ---help--- |
| 452 | This device-mapper target creates a device that supports an arbitrary |
| 453 | mapping of fixed-size regions of I/O across a fixed set of paths. |
| 454 | The path used for any specific region can be switched dynamically |
| 455 | by sending the target a message. |
| 456 | |
| 457 | To compile this code as a module, choose M here: the module will |
| 458 | be called dm-switch. |
| 459 | |
| 460 | If unsure, say N. |
| 461 | |
Josef Bacik | 0e9cebe | 2015-03-20 10:50:37 -0400 | [diff] [blame] | 462 | config DM_LOG_WRITES |
| 463 | tristate "Log writes target support" |
| 464 | depends on BLK_DEV_DM |
| 465 | ---help--- |
| 466 | This device-mapper target takes two devices, one device to use |
| 467 | normally, one to log all write operations done to the first device. |
| 468 | This is for use by file system developers wishing to verify that |
| 469 | their fs is writing a consitent file system at all times by allowing |
| 470 | them to replay the log in a variety of ways and to check the |
| 471 | contents. |
| 472 | |
| 473 | To compile this code as a module, choose M here: the module will |
| 474 | be called dm-log-writes. |
| 475 | |
| 476 | If unsure, say N. |
| 477 | |
Jan Engelhardt | afd4403 | 2007-07-17 04:06:11 -0700 | [diff] [blame] | 478 | endif # MD |