linux/drivers/md/Kconfig
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   1#
   2# Block device driver configuration
   3#
   4
   5menuconfig MD
   6        bool "Multiple devices driver support (RAID and LVM)"
   7        depends on BLOCK
   8        help
   9          Support multiple physical spindles through a single logical device.
  10          Required for RAID and logical volume management.
  11
  12if MD
  13
  14config BLK_DEV_MD
  15        tristate "RAID support"
  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
  33config MD_AUTODETECT
  34        bool "Autodetect RAID arrays during kernel boot"
  35        depends on BLK_DEV_MD=y
  36        default y
  37        ---help---
  38          If you say Y here, then the kernel will try to autodetect raid
  39          arrays as part of its boot process. 
  40
  41          If you don't use raid and say Y, this autodetection can cause 
  42          a several-second delay in the boot time due to various
  43          synchronisation steps that are part of this step.
  44
  45          If unsure, say Y.
  46
  47config MD_LINEAR
  48        tristate "Linear (append) mode"
  49        depends on BLK_DEV_MD
  50        ---help---
  51          If you say Y here, then your multiple devices driver will be able to
  52          use the so-called linear mode, i.e. it will combine the hard disk
  53          partitions by simply appending one to the other.
  54
  55          To compile this as a module, choose M here: the module
  56          will be called linear.
  57
  58          If unsure, say Y.
  59
  60config MD_RAID0
  61        tristate "RAID-0 (striping) mode"
  62        depends on BLK_DEV_MD
  63        ---help---
  64          If you say Y here, then your multiple devices driver will be able to
  65          use the so-called raid0 mode, i.e. it will combine the hard disk
  66          partitions into one logical device in such a fashion as to fill them
  67          up evenly, one chunk here and one chunk there. This will increase
  68          the throughput rate if the partitions reside on distinct disks.
  69
  70          Information about Software RAID on Linux is contained in the
  71          Software-RAID mini-HOWTO, available from
  72          <http://www.tldp.org/docs.html#howto>. There you will also
  73          learn where to get the supporting user space utilities raidtools.
  74
  75          To compile this as a module, choose M here: the module
  76          will be called raid0.
  77
  78          If unsure, say Y.
  79
  80config MD_RAID1
  81        tristate "RAID-1 (mirroring) mode"
  82        depends on BLK_DEV_MD
  83        ---help---
  84          A RAID-1 set consists of several disk drives which are exact copies
  85          of each other.  In the event of a mirror failure, the RAID driver
  86          will continue to use the operational mirrors in the set, providing
  87          an error free MD (multiple device) to the higher levels of the
  88          kernel.  In a set with N drives, the available space is the capacity
  89          of a single drive, and the set protects against a failure of (N - 1)
  90          drives.
  91
  92          Information about Software RAID on Linux is contained in the
  93          Software-RAID mini-HOWTO, available from
  94          <http://www.tldp.org/docs.html#howto>.  There you will also
  95          learn where to get the supporting user space utilities raidtools.
  96
  97          If you want to use such a RAID-1 set, say Y.  To compile this code
  98          as a module, choose M here: the module will be called raid1.
  99
 100          If unsure, say Y.
 101
 102config MD_RAID10
 103        tristate "RAID-10 (mirrored striping) mode"
 104        depends on BLK_DEV_MD
 105        ---help---
 106          RAID-10 provides a combination of striping (RAID-0) and
 107          mirroring (RAID-1) with easier configuration and more flexible
 108          layout.
 109          Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to
 110          be the same size (or at least, only as much as the smallest device
 111          will be used).
 112          RAID-10 provides a variety of layouts that provide different levels
 113          of redundancy and performance.
 114
 115          RAID-10 requires mdadm-1.7.0 or later, available at:
 116
 117          ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/
 118
 119          If unsure, say Y.
 120
 121config MD_RAID456
 122        tristate "RAID-4/RAID-5/RAID-6 mode"
 123        depends on BLK_DEV_MD
 124        select RAID6_PQ
 125        select ASYNC_MEMCPY
 126        select ASYNC_XOR
 127        select ASYNC_PQ
 128        select ASYNC_RAID6_RECOV
 129        ---help---
 130          A RAID-5 set of N drives with a capacity of C MB per drive provides
 131          the capacity of C * (N - 1) MB, and protects against a failure
 132          of a single drive. For a given sector (row) number, (N - 1) drives
 133          contain data sectors, and one drive contains the parity protection.
 134          For a RAID-4 set, the parity blocks are present on a single drive,
 135          while a RAID-5 set distributes the parity across the drives in one
 136          of the available parity distribution methods.
 137
 138          A RAID-6 set of N drives with a capacity of C MB per drive
 139          provides the capacity of C * (N - 2) MB, and protects
 140          against a failure of any two drives. For a given sector
 141          (row) number, (N - 2) drives contain data sectors, and two
 142          drives contains two independent redundancy syndromes.  Like
 143          RAID-5, RAID-6 distributes the syndromes across the drives
 144          in one of the available parity distribution methods.
 145
 146          Information about Software RAID on Linux is contained in the
 147          Software-RAID mini-HOWTO, available from
 148          <http://www.tldp.org/docs.html#howto>. There you will also
 149          learn where to get the supporting user space utilities raidtools.
 150
 151          If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y.  To
 152          compile this code as a module, choose M here: the module
 153          will be called raid456.
 154
 155          If unsure, say Y.
 156
 157config MD_MULTIPATH
 158        tristate "Multipath I/O support"
 159        depends on BLK_DEV_MD
 160        help
 161          MD_MULTIPATH provides a simple multi-path personality for use
 162          the MD framework.  It is not under active development.  New
 163          projects should consider using DM_MULTIPATH which has more
 164          features and more testing.
 165
 166          If unsure, say N.
 167
 168config MD_FAULTY
 169        tristate "Faulty test module for MD"
 170        depends on BLK_DEV_MD
 171        help
 172          The "faulty" module allows for a block device that occasionally returns
 173          read or write errors.  It is useful for testing.
 174
 175          In unsure, say N.
 176
 177config BLK_DEV_DM
 178        tristate "Device mapper support"
 179        ---help---
 180          Device-mapper is a low level volume manager.  It works by allowing
 181          people to specify mappings for ranges of logical sectors.  Various
 182          mapping types are available, in addition people may write their own
 183          modules containing custom mappings if they wish.
 184
 185          Higher level volume managers such as LVM2 use this driver.
 186
 187          To compile this as a module, choose M here: the module will be
 188          called dm-mod.
 189
 190          If unsure, say N.
 191
 192config DM_DEBUG
 193        boolean "Device mapper debugging support"
 194        depends on BLK_DEV_DM
 195        ---help---
 196          Enable this for messages that may help debug device-mapper problems.
 197
 198          If unsure, say N.
 199
 200config DM_BUFIO
 201       tristate
 202       depends on BLK_DEV_DM
 203       ---help---
 204         This interface allows you to do buffered I/O on a device and acts
 205         as a cache, holding recently-read blocks in memory and performing
 206         delayed writes.
 207
 208config DM_BIO_PRISON
 209       tristate
 210       depends on BLK_DEV_DM
 211       ---help---
 212         Some bio locking schemes used by other device-mapper targets
 213         including thin provisioning.
 214
 215source "drivers/md/persistent-data/Kconfig"
 216
 217config DM_CRYPT
 218        tristate "Crypt target support"
 219        depends on BLK_DEV_DM
 220        select CRYPTO
 221        select CRYPTO_CBC
 222        ---help---
 223          This device-mapper target allows you to create a device that
 224          transparently encrypts the data on it. You'll need to activate
 225          the ciphers you're going to use in the cryptoapi configuration.
 226
 227          Information on how to use dm-crypt can be found on
 228
 229          <http://www.saout.de/misc/dm-crypt/>
 230
 231          To compile this code as a module, choose M here: the module will
 232          be called dm-crypt.
 233
 234          If unsure, say N.
 235
 236config DM_SNAPSHOT
 237       tristate "Snapshot target"
 238       depends on BLK_DEV_DM
 239       ---help---
 240         Allow volume managers to take writable snapshots of a device.
 241
 242config DM_THIN_PROVISIONING
 243       tristate "Thin provisioning target"
 244       depends on BLK_DEV_DM
 245       select DM_PERSISTENT_DATA
 246       select DM_BIO_PRISON
 247       ---help---
 248         Provides thin provisioning and snapshots that share a data store.
 249
 250config DM_DEBUG_BLOCK_STACK_TRACING
 251        boolean "Keep stack trace of thin provisioning block lock holders"
 252        depends on STACKTRACE_SUPPORT && DM_THIN_PROVISIONING
 253        select STACKTRACE
 254        ---help---
 255          Enable this for messages that may help debug problems with the
 256          block manager locking used by thin provisioning.
 257
 258          If unsure, say N.
 259
 260config DM_CACHE
 261       tristate "Cache target (EXPERIMENTAL)"
 262       depends on BLK_DEV_DM
 263       default n
 264       select DM_PERSISTENT_DATA
 265       select DM_BIO_PRISON
 266       ---help---
 267         dm-cache attempts to improve performance of a block device by
 268         moving frequently used data to a smaller, higher performance
 269         device.  Different 'policy' plugins can be used to change the
 270         algorithms used to select which blocks are promoted, demoted,
 271         cleaned etc.  It supports writeback and writethrough modes.
 272
 273config DM_CACHE_MQ
 274       tristate "MQ Cache Policy (EXPERIMENTAL)"
 275       depends on DM_CACHE
 276       default y
 277       ---help---
 278         A cache policy that uses a multiqueue ordered by recent hit
 279         count to select which blocks should be promoted and demoted.
 280         This is meant to be a general purpose policy.  It prioritises
 281         reads over writes.
 282
 283config DM_CACHE_CLEANER
 284       tristate "Cleaner Cache Policy (EXPERIMENTAL)"
 285       depends on DM_CACHE
 286       default y
 287       ---help---
 288         A simple cache policy that writes back all data to the
 289         origin.  Used when decommissioning a dm-cache.
 290
 291config DM_MIRROR
 292       tristate "Mirror target"
 293       depends on BLK_DEV_DM
 294       ---help---
 295         Allow volume managers to mirror logical volumes, also
 296         needed for live data migration tools such as 'pvmove'.
 297
 298config DM_RAID
 299       tristate "RAID 1/4/5/6/10 target"
 300       depends on BLK_DEV_DM
 301       select MD_RAID1
 302       select MD_RAID10
 303       select MD_RAID456
 304       select BLK_DEV_MD
 305       ---help---
 306         A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings
 307
 308         A RAID-5 set of N drives with a capacity of C MB per drive provides
 309         the capacity of C * (N - 1) MB, and protects against a failure
 310         of a single drive. For a given sector (row) number, (N - 1) drives
 311         contain data sectors, and one drive contains the parity protection.
 312         For a RAID-4 set, the parity blocks are present on a single drive,
 313         while a RAID-5 set distributes the parity across the drives in one
 314         of the available parity distribution methods.
 315
 316         A RAID-6 set of N drives with a capacity of C MB per drive
 317         provides the capacity of C * (N - 2) MB, and protects
 318         against a failure of any two drives. For a given sector
 319         (row) number, (N - 2) drives contain data sectors, and two
 320         drives contains two independent redundancy syndromes.  Like
 321         RAID-5, RAID-6 distributes the syndromes across the drives
 322         in one of the available parity distribution methods.
 323
 324config DM_LOG_USERSPACE
 325        tristate "Mirror userspace logging"
 326        depends on DM_MIRROR && NET
 327        select CONNECTOR
 328        ---help---
 329          The userspace logging module provides a mechanism for
 330          relaying the dm-dirty-log API to userspace.  Log designs
 331          which are more suited to userspace implementation (e.g.
 332          shared storage logs) or experimental logs can be implemented
 333          by leveraging this framework.
 334
 335config DM_ZERO
 336        tristate "Zero target"
 337        depends on BLK_DEV_DM
 338        ---help---
 339          A target that discards writes, and returns all zeroes for
 340          reads.  Useful in some recovery situations.
 341
 342config DM_MULTIPATH
 343        tristate "Multipath target"
 344        depends on BLK_DEV_DM
 345        # nasty syntax but means make DM_MULTIPATH independent
 346        # of SCSI_DH if the latter isn't defined but if
 347        # it is, DM_MULTIPATH must depend on it.  We get a build
 348        # error if SCSI_DH=m and DM_MULTIPATH=y
 349        depends on SCSI_DH || !SCSI_DH
 350        ---help---
 351          Allow volume managers to support multipath hardware.
 352
 353config DM_MULTIPATH_QL
 354        tristate "I/O Path Selector based on the number of in-flight I/Os"
 355        depends on DM_MULTIPATH
 356        ---help---
 357          This path selector is a dynamic load balancer which selects
 358          the path with the least number of in-flight I/Os.
 359
 360          If unsure, say N.
 361
 362config DM_MULTIPATH_ST
 363        tristate "I/O Path Selector based on the service time"
 364        depends on DM_MULTIPATH
 365        ---help---
 366          This path selector is a dynamic load balancer which selects
 367          the path expected to complete the incoming I/O in the shortest
 368          time.
 369
 370          If unsure, say N.
 371
 372config DM_DELAY
 373        tristate "I/O delaying target"
 374        depends on BLK_DEV_DM
 375        ---help---
 376        A target that delays reads and/or writes and can send
 377        them to different devices.  Useful for testing.
 378
 379        If unsure, say N.
 380
 381config DM_UEVENT
 382        bool "DM uevents"
 383        depends on BLK_DEV_DM
 384        ---help---
 385        Generate udev events for DM events.
 386
 387config DM_FLAKEY
 388       tristate "Flakey target"
 389       depends on BLK_DEV_DM
 390       ---help---
 391         A target that intermittently fails I/O for debugging purposes.
 392
 393config DM_VERITY
 394        tristate "Verity target support"
 395        depends on BLK_DEV_DM
 396        select CRYPTO
 397        select CRYPTO_HASH
 398        select DM_BUFIO
 399        ---help---
 400          This device-mapper target creates a read-only device that
 401          transparently validates the data on one underlying device against
 402          a pre-generated tree of cryptographic checksums stored on a second
 403          device.
 404
 405          You'll need to activate the digests you're going to use in the
 406          cryptoapi configuration.
 407
 408          To compile this code as a module, choose M here: the module will
 409          be called dm-verity.
 410
 411          If unsure, say N.
 412
 413endif # MD
 414
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