drivers/md/Kconfig

   1 #
   2 # Block device driver configuration
   3 #
   4
   5 menuconfig 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
  12 if MD
  13
  14 config 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
  33 config 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
  47 config 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
  60 config 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
  80 config 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
 102 config 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
 121 config 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
 157 config MULTICORE_RAID456
 158         bool "RAID-4/RAID-5/RAID-6 Multicore processing (EXPERIMENTAL)"
 159         depends on MD_RAID456
 160         depends on SMP
 161         depends on EXPERIMENTAL
 162         ---help---
 163           Enable the raid456 module to dispatch per-stripe raid operations to a
 164           thread pool.
 165
 166           If unsure, say N.
 167
 168 config MD_MULTIPATH
 169         tristate "Multipath I/O support"
 170         depends on BLK_DEV_MD
 171         help
 172           MD_MULTIPATH provides a simple multi-path personality for use
 173           the MD framework.  It is not under active development.  New
 174           projects should consider using DM_MULTIPATH which has more
 175           features and more testing.
 176
 177           If unsure, say N.
 178
 179 config MD_FAULTY
 180         tristate "Faulty test module for MD"
 181         depends on BLK_DEV_MD
 182         help
 183           The "faulty" module allows for a block device that occasionally returns
 184           read or write errors.  It is useful for testing.
 185
 186           In unsure, say N.
 187
 188 config BLK_DEV_DM
 189         tristate "Device mapper support"
 190         ---help---
 191           Device-mapper is a low level volume manager.  It works by allowing
 192           people to specify mappings for ranges of logical sectors.  Various
 193           mapping types are available, in addition people may write their own
 194           modules containing custom mappings if they wish.
 195
 196           Higher level volume managers such as LVM2 use this driver.
 197
 198           To compile this as a module, choose M here: the module will be
 199           called dm-mod.
 200
 201           If unsure, say N.
 202
 203 config DM_DEBUG
 204         boolean "Device mapper debugging support"
 205         depends on BLK_DEV_DM
 206         ---help---
 207           Enable this for messages that may help debug device-mapper problems.
 208
 209           If unsure, say N.
 210
 211 config DM_BUFIO
 212        tristate
 213        depends on BLK_DEV_DM
 214        ---help---
 215          This interface allows you to do buffered I/O on a device and acts
 216          as a cache, holding recently-read blocks in memory and performing
 217          delayed writes.
 218
 219 config DM_BIO_PRISON
 220        tristate
 221        depends on BLK_DEV_DM
 222        ---help---
 223          Some bio locking schemes used by other device-mapper targets
 224          including thin provisioning.
 225
 226 source "drivers/md/persistent-data/Kconfig"
 227
 228 config DM_CRYPT
 229         tristate "Crypt target support"
 230         depends on BLK_DEV_DM
 231         select CRYPTO
 232         select CRYPTO_CBC
 233         ---help---
 234           This device-mapper target allows you to create a device that
 235           transparently encrypts the data on it. You'll need to activate
 236           the ciphers you're going to use in the cryptoapi configuration.
 237
 238           Information on how to use dm-crypt can be found on
 239
 240           <http://www.saout.de/misc/dm-crypt/>
 241
 242           To compile this code as a module, choose M here: the module will
 243           be called dm-crypt.
 244
 245           If unsure, say N.
 246
 247 config DM_SNAPSHOT
 248        tristate "Snapshot target"
 249        depends on BLK_DEV_DM
 250        ---help---
 251          Allow volume managers to take writable snapshots of a device.
 252
 253 config DM_THIN_PROVISIONING
 254        tristate "Thin provisioning target"
 255        depends on BLK_DEV_DM
 256        select DM_PERSISTENT_DATA
 257        select DM_BIO_PRISON
 258        ---help---
 259          Provides thin provisioning and snapshots that share a data store.
 260
 261 config DM_DEBUG_BLOCK_STACK_TRACING
 262         boolean "Keep stack trace of thin provisioning block lock holders"
 263         depends on STACKTRACE_SUPPORT && DM_THIN_PROVISIONING
 264         select STACKTRACE
 265         ---help---
 266           Enable this for messages that may help debug problems with the
 267           block manager locking used by thin provisioning.
 268
 269           If unsure, say N.
 270
 271 config DM_CACHE
 272        tristate "Cache target (EXPERIMENTAL)"
 273        depends on BLK_DEV_DM
 274        default n
 275        select DM_PERSISTENT_DATA
 276        select DM_BIO_PRISON
 277        ---help---
 278          dm-cache attempts to improve performance of a block device by
 279          moving frequently used data to a smaller, higher performance
 280          device.  Different 'policy' plugins can be used to change the
 281          algorithms used to select which blocks are promoted, demoted,
 282          cleaned etc.  It supports writeback and writethrough modes.
 283
 284 config DM_CACHE_MQ
 285        tristate "MQ Cache Policy (EXPERIMENTAL)"
 286        depends on DM_CACHE
 287        default y
 288        ---help---
 289          A cache policy that uses a multiqueue ordered by recent hit
 290          count to select which blocks should be promoted and demoted.
 291          This is meant to be a general purpose policy.  It prioritises
 292          reads over writes.
 293
 294 config DM_CACHE_CLEANER
 295        tristate "Cleaner Cache Policy (EXPERIMENTAL)"
 296        depends on DM_CACHE
 297        default y
 298        ---help---
 299          A simple cache policy that writes back all data to the
 300          origin.  Used when decommissioning a dm-cache.
 301
 302 config DM_MIRROR
 303        tristate "Mirror target"
 304        depends on BLK_DEV_DM
 305        ---help---
 306          Allow volume managers to mirror logical volumes, also
 307          needed for live data migration tools such as 'pvmove'.
 308
 309 config DM_RAID
 310        tristate "RAID 1/4/5/6/10 target"
 311        depends on BLK_DEV_DM
 312        select MD_RAID1
 313        select MD_RAID10
 314        select MD_RAID456
 315        select BLK_DEV_MD
 316        ---help---
 317          A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings
 318
 319          A RAID-5 set of N drives with a capacity of C MB per drive provides
 320          the capacity of C * (N - 1) MB, and protects against a failure
 321          of a single drive. For a given sector (row) number, (N - 1) drives
 322          contain data sectors, and one drive contains the parity protection.
 323          For a RAID-4 set, the parity blocks are present on a single drive,
 324          while a RAID-5 set distributes the parity across the drives in one
 325          of the available parity distribution methods.
 326
 327          A RAID-6 set of N drives with a capacity of C MB per drive
 328          provides the capacity of C * (N - 2) MB, and protects
 329          against a failure of any two drives. For a given sector
 330          (row) number, (N - 2) drives contain data sectors, and two
 331          drives contains two independent redundancy syndromes.  Like
 332          RAID-5, RAID-6 distributes the syndromes across the drives
 333          in one of the available parity distribution methods.
 334
 335 config DM_LOG_USERSPACE
 336         tristate "Mirror userspace logging"
 337         depends on DM_MIRROR && NET
 338         select CONNECTOR
 339         ---help---
 340           The userspace logging module provides a mechanism for
 341           relaying the dm-dirty-log API to userspace.  Log designs
 342           which are more suited to userspace implementation (e.g.
 343           shared storage logs) or experimental logs can be implemented
 344           by leveraging this framework.
 345
 346 config DM_ZERO
 347         tristate "Zero target"
 348         depends on BLK_DEV_DM
 349         ---help---
 350           A target that discards writes, and returns all zeroes for
 351           reads.  Useful in some recovery situations.
 352
 353 config DM_MULTIPATH
 354         tristate "Multipath target"
 355         depends on BLK_DEV_DM
 356         # nasty syntax but means make DM_MULTIPATH independent
 357         # of SCSI_DH if the latter isn't defined but if
 358         # it is, DM_MULTIPATH must depend on it.  We get a build
 359         # error if SCSI_DH=m and DM_MULTIPATH=y
 360         depends on SCSI_DH || !SCSI_DH
 361         ---help---
 362           Allow volume managers to support multipath hardware.
 363
 364 config DM_MULTIPATH_QL
 365         tristate "I/O Path Selector based on the number of in-flight I/Os"
 366         depends on DM_MULTIPATH
 367         ---help---
 368           This path selector is a dynamic load balancer which selects
 369           the path with the least number of in-flight I/Os.
 370
 371           If unsure, say N.
 372
 373 config DM_MULTIPATH_ST
 374         tristate "I/O Path Selector based on the service time"
 375         depends on DM_MULTIPATH
 376         ---help---
 377           This path selector is a dynamic load balancer which selects
 378           the path expected to complete the incoming I/O in the shortest
 379           time.
 380
 381           If unsure, say N.
 382
 383 config DM_DELAY
 384         tristate "I/O delaying target"
 385         depends on BLK_DEV_DM
 386         ---help---
 387         A target that delays reads and/or writes and can send
 388         them to different devices.  Useful for testing.
 389
 390         If unsure, say N.
 391
 392 config DM_UEVENT
 393         bool "DM uevents"
 394         depends on BLK_DEV_DM
 395         ---help---
 396         Generate udev events for DM events.
 397
 398 config DM_FLAKEY
 399        tristate "Flakey target"
 400        depends on BLK_DEV_DM
 401        ---help---
 402          A target that intermittently fails I/O for debugging purposes.
 403
 404 config DM_VERITY
 405         tristate "Verity target support"
 406         depends on BLK_DEV_DM
 407         select CRYPTO
 408         select CRYPTO_HASH
 409         select DM_BUFIO
 410         ---help---
 411           This device-mapper target creates a read-only device that
 412           transparently validates the data on one underlying device against
 413           a pre-generated tree of cryptographic checksums stored on a second
 414           device.
 415
 416           You'll need to activate the digests you're going to use in the
 417           cryptoapi configuration.
 418
 419           To compile this code as a module, choose M here: the module will
 420           be called dm-verity.
 421
 422           If unsure, say N.
 423
 424 endif # MD