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
 177source "drivers/md/bcache/Kconfig"
 178
 179config BLK_DEV_DM
 180        tristate "Device mapper support"
 181        ---help---
 182          Device-mapper is a low level volume manager.  It works by allowing
 183          people to specify mappings for ranges of logical sectors.  Various
 184          mapping types are available, in addition people may write their own
 185          modules containing custom mappings if they wish.
 186
 187          Higher level volume managers such as LVM2 use this driver.
 188
 189          To compile this as a module, choose M here: the module will be
 190          called dm-mod.
 191
 192          If unsure, say N.
 193
 194config DM_DEBUG
 195        boolean "Device mapper debugging support"
 196        depends on BLK_DEV_DM
 197        ---help---
 198          Enable this for messages that may help debug device-mapper problems.
 199
 200          If unsure, say N.
 201
 202config DM_BUFIO
 203       tristate
 204       depends on BLK_DEV_DM
 205       ---help---
 206         This interface allows you to do buffered I/O on a device and acts
 207         as a cache, holding recently-read blocks in memory and performing
 208         delayed writes.
 209
 210config DM_BIO_PRISON
 211       tristate
 212       depends on BLK_DEV_DM
 213       ---help---
 214         Some bio locking schemes used by other device-mapper targets
 215         including thin provisioning.
 216
 217source "drivers/md/persistent-data/Kconfig"
 218
 219config DM_CRYPT
 220        tristate "Crypt target support"
 221        depends on BLK_DEV_DM
 222        select CRYPTO
 223        select CRYPTO_CBC
 224        ---help---
 225          This device-mapper target allows you to create a device that
 226          transparently encrypts the data on it. You'll need to activate
 227          the ciphers you're going to use in the cryptoapi configuration.
 228
 229          Information on how to use dm-crypt can be found on
 230
 231          <http://www.saout.de/misc/dm-crypt/>
 232
 233          To compile this code as a module, choose M here: the module will
 234          be called dm-crypt.
 235
 236          If unsure, say N.
 237
 238config DM_SNAPSHOT
 239       tristate "Snapshot target"
 240       depends on BLK_DEV_DM
 241       ---help---
 242         Allow volume managers to take writable snapshots of a device.
 243
 244config DM_THIN_PROVISIONING
 245       tristate "Thin provisioning target"
 246       depends on BLK_DEV_DM
 247       select DM_PERSISTENT_DATA
 248       select DM_BIO_PRISON
 249       ---help---
 250         Provides thin provisioning and snapshots that share a data store.
 251
 252config DM_DEBUG_BLOCK_STACK_TRACING
 253        boolean "Keep stack trace of thin provisioning block lock holders"
 254        depends on STACKTRACE_SUPPORT && DM_THIN_PROVISIONING
 255        select STACKTRACE
 256        ---help---
 257          Enable this for messages that may help debug problems with the
 258          block manager locking used by thin provisioning.
 259
 260          If unsure, say N.
 261
 262config DM_CACHE
 263       tristate "Cache target (EXPERIMENTAL)"
 264       depends on BLK_DEV_DM
 265       default n
 266       select DM_PERSISTENT_DATA
 267       select DM_BIO_PRISON
 268       ---help---
 269         dm-cache attempts to improve performance of a block device by
 270         moving frequently used data to a smaller, higher performance
 271         device.  Different 'policy' plugins can be used to change the
 272         algorithms used to select which blocks are promoted, demoted,
 273         cleaned etc.  It supports writeback and writethrough modes.
 274
 275config DM_CACHE_MQ
 276       tristate "MQ Cache Policy (EXPERIMENTAL)"
 277       depends on DM_CACHE
 278       default y
 279       ---help---
 280         A cache policy that uses a multiqueue ordered by recent hit
 281         count to select which blocks should be promoted and demoted.
 282         This is meant to be a general purpose policy.  It prioritises
 283         reads over writes.
 284
 285config DM_CACHE_CLEANER
 286       tristate "Cleaner Cache Policy (EXPERIMENTAL)"
 287       depends on DM_CACHE
 288       default y
 289       ---help---
 290         A simple cache policy that writes back all data to the
 291         origin.  Used when decommissioning a dm-cache.
 292
 293config DM_MIRROR
 294       tristate "Mirror target"
 295       depends on BLK_DEV_DM
 296       ---help---
 297         Allow volume managers to mirror logical volumes, also
 298         needed for live data migration tools such as 'pvmove'.
 299
 300config DM_RAID
 301       tristate "RAID 1/4/5/6/10 target"
 302       depends on BLK_DEV_DM
 303       select MD_RAID1
 304       select MD_RAID10
 305       select MD_RAID456
 306       select BLK_DEV_MD
 307       ---help---
 308         A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings
 309
 310         A RAID-5 set of N drives with a capacity of C MB per drive provides
 311         the capacity of C * (N - 1) MB, and protects against a failure
 312         of a single drive. For a given sector (row) number, (N - 1) drives
 313         contain data sectors, and one drive contains the parity protection.
 314         For a RAID-4 set, the parity blocks are present on a single drive,
 315         while a RAID-5 set distributes the parity across the drives in one
 316         of the available parity distribution methods.
 317
 318         A RAID-6 set of N drives with a capacity of C MB per drive
 319         provides the capacity of C * (N - 2) MB, and protects
 320         against a failure of any two drives. For a given sector
 321         (row) number, (N - 2) drives contain data sectors, and two
 322         drives contains two independent redundancy syndromes.  Like
 323         RAID-5, RAID-6 distributes the syndromes across the drives
 324         in one of the available parity distribution methods.
 325
 326config DM_LOG_USERSPACE
 327        tristate "Mirror userspace logging"
 328        depends on DM_MIRROR && NET
 329        select CONNECTOR
 330        ---help---
 331          The userspace logging module provides a mechanism for
 332          relaying the dm-dirty-log API to userspace.  Log designs
 333          which are more suited to userspace implementation (e.g.
 334          shared storage logs) or experimental logs can be implemented
 335          by leveraging this framework.
 336
 337config DM_ZERO
 338        tristate "Zero target"
 339        depends on BLK_DEV_DM
 340        ---help---
 341          A target that discards writes, and returns all zeroes for
 342          reads.  Useful in some recovery situations.
 343
 344config DM_MULTIPATH
 345        tristate "Multipath target"
 346        depends on BLK_DEV_DM
 347        # nasty syntax but means make DM_MULTIPATH independent
 348        # of SCSI_DH if the latter isn't defined but if
 349        # it is, DM_MULTIPATH must depend on it.  We get a build
 350        # error if SCSI_DH=m and DM_MULTIPATH=y
 351        depends on SCSI_DH || !SCSI_DH
 352        ---help---
 353          Allow volume managers to support multipath hardware.
 354
 355config DM_MULTIPATH_QL
 356        tristate "I/O Path Selector based on the number of in-flight I/Os"
 357        depends on DM_MULTIPATH
 358        ---help---
 359          This path selector is a dynamic load balancer which selects
 360          the path with the least number of in-flight I/Os.
 361
 362          If unsure, say N.
 363
 364config DM_MULTIPATH_ST
 365        tristate "I/O Path Selector based on the service time"
 366        depends on DM_MULTIPATH
 367        ---help---
 368          This path selector is a dynamic load balancer which selects
 369          the path expected to complete the incoming I/O in the shortest
 370          time.
 371
 372          If unsure, say N.
 373
 374config DM_DELAY
 375        tristate "I/O delaying target"
 376        depends on BLK_DEV_DM
 377        ---help---
 378        A target that delays reads and/or writes and can send
 379        them to different devices.  Useful for testing.
 380
 381        If unsure, say N.
 382
 383config DM_UEVENT
 384        bool "DM uevents"
 385        depends on BLK_DEV_DM
 386        ---help---
 387        Generate udev events for DM events.
 388
 389config DM_FLAKEY
 390       tristate "Flakey target"
 391       depends on BLK_DEV_DM
 392       ---help---
 393         A target that intermittently fails I/O for debugging purposes.
 394
 395config DM_VERITY
 396        tristate "Verity target support"
 397        depends on BLK_DEV_DM
 398        select CRYPTO
 399        select CRYPTO_HASH
 400        select DM_BUFIO
 401        ---help---
 402          This device-mapper target creates a read-only device that
 403          transparently validates the data on one underlying device against
 404          a pre-generated tree of cryptographic checksums stored on a second
 405          device.
 406
 407          You'll need to activate the digests you're going to use in the
 408          cryptoapi configuration.
 409
 410          To compile this code as a module, choose M here: the module will
 411          be called dm-verity.
 412
 413          If unsure, say N.
 414
 415config DM_SWITCH
 416        tristate "Switch target support (EXPERIMENTAL)"
 417        depends on BLK_DEV_DM
 418        ---help---
 419          This device-mapper target creates a device that supports an arbitrary
 420          mapping of fixed-size regions of I/O across a fixed set of paths.
 421          The path used for any specific region can be switched dynamically
 422          by sending the target a message.
 423
 424          To compile this code as a module, choose M here: the module will
 425          be called dm-switch.
 426
 427          If unsure, say N.
 428
 429endif # MD
 430
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