Kconfig 9.8 KB

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  1. #
  2. # Block device driver configuration
  3. #
  4. menuconfig MD
  5. bool "Multiple devices driver support (RAID and LVM)"
  6. depends on BLOCK
  7. help
  8. Support multiple physical spindles through a single logical device.
  9. Required for RAID and logical volume management.
  10. if MD
  11. config BLK_DEV_MD
  12. tristate "RAID support"
  13. ---help---
  14. This driver lets you combine several hard disk partitions into one
  15. logical block device. This can be used to simply append one
  16. partition to another one or to combine several redundant hard disks
  17. into a RAID1/4/5 device so as to provide protection against hard
  18. disk failures. This is called "Software RAID" since the combining of
  19. the partitions is done by the kernel. "Hardware RAID" means that the
  20. combining is done by a dedicated controller; if you have such a
  21. controller, you do not need to say Y here.
  22. More information about Software RAID on Linux is contained in the
  23. Software RAID mini-HOWTO, available from
  24. <http://www.tldp.org/docs.html#howto>. There you will also learn
  25. where to get the supporting user space utilities raidtools.
  26. If unsure, say N.
  27. config MD_AUTODETECT
  28. bool "Autodetect RAID arrays during kernel boot"
  29. depends on BLK_DEV_MD=y
  30. default y
  31. ---help---
  32. If you say Y here, then the kernel will try to autodetect raid
  33. arrays as part of its boot process.
  34. If you don't use raid and say Y, this autodetection can cause
  35. a several-second delay in the boot time due to various
  36. synchronisation steps that are part of this step.
  37. If unsure, say Y.
  38. config MD_LINEAR
  39. tristate "Linear (append) mode"
  40. depends on BLK_DEV_MD
  41. ---help---
  42. If you say Y here, then your multiple devices driver will be able to
  43. use the so-called linear mode, i.e. it will combine the hard disk
  44. partitions by simply appending one to the other.
  45. To compile this as a module, choose M here: the module
  46. will be called linear.
  47. If unsure, say Y.
  48. config MD_RAID0
  49. tristate "RAID-0 (striping) 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 raid0 mode, i.e. it will combine the hard disk
  54. partitions into one logical device in such a fashion as to fill them
  55. up evenly, one chunk here and one chunk there. This will increase
  56. the throughput rate if the partitions reside on distinct disks.
  57. Information about Software RAID on Linux is contained in the
  58. Software-RAID mini-HOWTO, available from
  59. <http://www.tldp.org/docs.html#howto>. There you will also
  60. learn where to get the supporting user space utilities raidtools.
  61. To compile this as a module, choose M here: the module
  62. will be called raid0.
  63. If unsure, say Y.
  64. config MD_RAID1
  65. tristate "RAID-1 (mirroring) mode"
  66. depends on BLK_DEV_MD
  67. ---help---
  68. A RAID-1 set consists of several disk drives which are exact copies
  69. of each other. In the event of a mirror failure, the RAID driver
  70. will continue to use the operational mirrors in the set, providing
  71. an error free MD (multiple device) to the higher levels of the
  72. kernel. In a set with N drives, the available space is the capacity
  73. of a single drive, and the set protects against a failure of (N - 1)
  74. drives.
  75. Information about Software RAID on Linux is contained in the
  76. Software-RAID mini-HOWTO, available from
  77. <http://www.tldp.org/docs.html#howto>. There you will also
  78. learn where to get the supporting user space utilities raidtools.
  79. If you want to use such a RAID-1 set, say Y. To compile this code
  80. as a module, choose M here: the module will be called raid1.
  81. If unsure, say Y.
  82. config MD_RAID10
  83. tristate "RAID-10 (mirrored striping) mode (EXPERIMENTAL)"
  84. depends on BLK_DEV_MD && EXPERIMENTAL
  85. ---help---
  86. RAID-10 provides a combination of striping (RAID-0) and
  87. mirroring (RAID-1) with easier configuration and more flexible
  88. layout.
  89. Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to
  90. be the same size (or at least, only as much as the smallest device
  91. will be used).
  92. RAID-10 provides a variety of layouts that provide different levels
  93. of redundancy and performance.
  94. RAID-10 requires mdadm-1.7.0 or later, available at:
  95. ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/
  96. If unsure, say Y.
  97. config MD_RAID456
  98. tristate "RAID-4/RAID-5/RAID-6 mode"
  99. depends on BLK_DEV_MD
  100. select MD_RAID6_PQ
  101. select ASYNC_MEMCPY
  102. select ASYNC_XOR
  103. ---help---
  104. A RAID-5 set of N drives with a capacity of C MB per drive provides
  105. the capacity of C * (N - 1) MB, and protects against a failure
  106. of a single drive. For a given sector (row) number, (N - 1) drives
  107. contain data sectors, and one drive contains the parity protection.
  108. For a RAID-4 set, the parity blocks are present on a single drive,
  109. while a RAID-5 set distributes the parity across the drives in one
  110. of the available parity distribution methods.
  111. A RAID-6 set of N drives with a capacity of C MB per drive
  112. provides the capacity of C * (N - 2) MB, and protects
  113. against a failure of any two drives. For a given sector
  114. (row) number, (N - 2) drives contain data sectors, and two
  115. drives contains two independent redundancy syndromes. Like
  116. RAID-5, RAID-6 distributes the syndromes across the drives
  117. in one of the available parity distribution methods.
  118. Information about Software RAID on Linux is contained in the
  119. Software-RAID mini-HOWTO, available from
  120. <http://www.tldp.org/docs.html#howto>. There you will also
  121. learn where to get the supporting user space utilities raidtools.
  122. If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To
  123. compile this code as a module, choose M here: the module
  124. will be called raid456.
  125. If unsure, say Y.
  126. config MD_RAID5_RESHAPE
  127. bool "Support adding drives to a raid-5 array"
  128. depends on MD_RAID456
  129. default y
  130. ---help---
  131. A RAID-5 set can be expanded by adding extra drives. This
  132. requires "restriping" the array which means (almost) every
  133. block must be written to a different place.
  134. This option allows such restriping to be done while the array
  135. is online.
  136. You will need mdadm version 2.4.1 or later to use this
  137. feature safely. During the early stage of reshape there is
  138. a critical section where live data is being over-written. A
  139. crash during this time needs extra care for recovery. The
  140. newer mdadm takes a copy of the data in the critical section
  141. and will restore it, if necessary, after a crash.
  142. The mdadm usage is e.g.
  143. mdadm --grow /dev/md1 --raid-disks=6
  144. to grow '/dev/md1' to having 6 disks.
  145. Note: The array can only be expanded, not contracted.
  146. There should be enough spares already present to make the new
  147. array workable.
  148. If unsure, say Y.
  149. config MD_RAID6_PQ
  150. tristate
  151. config MD_MULTIPATH
  152. tristate "Multipath I/O support"
  153. depends on BLK_DEV_MD
  154. help
  155. Multipath-IO is the ability of certain devices to address the same
  156. physical disk over multiple 'IO paths'. The code ensures that such
  157. paths can be defined and handled at runtime, and ensures that a
  158. transparent failover to the backup path(s) happens if a IO errors
  159. arrives on the primary path.
  160. If unsure, say N.
  161. config MD_FAULTY
  162. tristate "Faulty test module for MD"
  163. depends on BLK_DEV_MD
  164. help
  165. The "faulty" module allows for a block device that occasionally returns
  166. read or write errors. It is useful for testing.
  167. In unsure, say N.
  168. config BLK_DEV_DM
  169. tristate "Device mapper support"
  170. ---help---
  171. Device-mapper is a low level volume manager. It works by allowing
  172. people to specify mappings for ranges of logical sectors. Various
  173. mapping types are available, in addition people may write their own
  174. modules containing custom mappings if they wish.
  175. Higher level volume managers such as LVM2 use this driver.
  176. To compile this as a module, choose M here: the module will be
  177. called dm-mod.
  178. If unsure, say N.
  179. config DM_DEBUG
  180. boolean "Device mapper debugging support"
  181. depends on BLK_DEV_DM
  182. ---help---
  183. Enable this for messages that may help debug device-mapper problems.
  184. If unsure, say N.
  185. config DM_CRYPT
  186. tristate "Crypt target support"
  187. depends on BLK_DEV_DM
  188. select CRYPTO
  189. select CRYPTO_CBC
  190. ---help---
  191. This device-mapper target allows you to create a device that
  192. transparently encrypts the data on it. You'll need to activate
  193. the ciphers you're going to use in the cryptoapi configuration.
  194. Information on how to use dm-crypt can be found on
  195. <http://www.saout.de/misc/dm-crypt/>
  196. To compile this code as a module, choose M here: the module will
  197. be called dm-crypt.
  198. If unsure, say N.
  199. config DM_SNAPSHOT
  200. tristate "Snapshot target"
  201. depends on BLK_DEV_DM
  202. ---help---
  203. Allow volume managers to take writable snapshots of a device.
  204. config DM_MIRROR
  205. tristate "Mirror target"
  206. depends on BLK_DEV_DM
  207. ---help---
  208. Allow volume managers to mirror logical volumes, also
  209. needed for live data migration tools such as 'pvmove'.
  210. config DM_ZERO
  211. tristate "Zero target"
  212. depends on BLK_DEV_DM
  213. ---help---
  214. A target that discards writes, and returns all zeroes for
  215. reads. Useful in some recovery situations.
  216. config DM_MULTIPATH
  217. tristate "Multipath target"
  218. depends on BLK_DEV_DM
  219. # nasty syntax but means make DM_MULTIPATH independent
  220. # of SCSI_DH if the latter isn't defined but if
  221. # it is, DM_MULTIPATH must depend on it. We get a build
  222. # error if SCSI_DH=m and DM_MULTIPATH=y
  223. depends on SCSI_DH || !SCSI_DH
  224. ---help---
  225. Allow volume managers to support multipath hardware.
  226. config DM_DELAY
  227. tristate "I/O delaying target (EXPERIMENTAL)"
  228. depends on BLK_DEV_DM && EXPERIMENTAL
  229. ---help---
  230. A target that delays reads and/or writes and can send
  231. them to different devices. Useful for testing.
  232. If unsure, say N.
  233. config DM_UEVENT
  234. bool "DM uevents (EXPERIMENTAL)"
  235. depends on BLK_DEV_DM && EXPERIMENTAL
  236. ---help---
  237. Generate udev events for DM events.
  238. endif # MD