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 && EXPERIMENTAL
 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 source "drivers/md/persistent-data/Kconfig"
 220
 221 config DM_CRYPT
 222         tristate "Crypt target support"
 223         depends on BLK_DEV_DM
 224         select CRYPTO
 225         select CRYPTO_CBC
 226         ---help---
 227           This device-mapper target allows you to create a device that
 228           transparently encrypts the data on it. You'll need to activate
 229           the ciphers you're going to use in the cryptoapi configuration.
 230
 231           Information on how to use dm-crypt can be found on
 232
 233           <http://www.saout.de/misc/dm-crypt/>
 234
 235           To compile this code as a module, choose M here: the module will
 236           be called dm-crypt.
 237
 238           If unsure, say N.
 239
 240 config DM_SNAPSHOT
 241        tristate "Snapshot target"
 242        depends on BLK_DEV_DM
 243        ---help---
 244          Allow volume managers to take writable snapshots of a device.
 245
 246 config DM_THIN_PROVISIONING
 247        tristate "Thin provisioning target (EXPERIMENTAL)"
 248        depends on BLK_DEV_DM && EXPERIMENTAL
 249        select DM_PERSISTENT_DATA
 250        ---help---
 251          Provides thin provisioning and snapshots that share a data store.
 252
 253 config DM_DEBUG_BLOCK_STACK_TRACING
 254         boolean "Keep stack trace of thin provisioning block lock holders"
 255         depends on STACKTRACE_SUPPORT && DM_THIN_PROVISIONING
 256         select STACKTRACE
 257         ---help---
 258           Enable this for messages that may help debug problems with the
 259           block manager locking used by thin provisioning.
 260
 261           If unsure, say N.
 262
 263 config DM_MIRROR
 264        tristate "Mirror target"
 265        depends on BLK_DEV_DM
 266        ---help---
 267          Allow volume managers to mirror logical volumes, also
 268          needed for live data migration tools such as 'pvmove'.
 269
 270 config DM_RAID
 271        tristate "RAID 1/4/5/6 target"
 272        depends on BLK_DEV_DM
 273        select MD_RAID1
 274        select MD_RAID456
 275        select BLK_DEV_MD
 276        ---help---
 277          A dm target that supports RAID1, RAID4, RAID5 and RAID6 mappings
 278
 279          A RAID-5 set of N drives with a capacity of C MB per drive provides
 280          the capacity of C * (N - 1) MB, and protects against a failure
 281          of a single drive. For a given sector (row) number, (N - 1) drives
 282          contain data sectors, and one drive contains the parity protection.
 283          For a RAID-4 set, the parity blocks are present on a single drive,
 284          while a RAID-5 set distributes the parity across the drives in one
 285          of the available parity distribution methods.
 286
 287          A RAID-6 set of N drives with a capacity of C MB per drive
 288          provides the capacity of C * (N - 2) MB, and protects
 289          against a failure of any two drives. For a given sector
 290          (row) number, (N - 2) drives contain data sectors, and two
 291          drives contains two independent redundancy syndromes.  Like
 292          RAID-5, RAID-6 distributes the syndromes across the drives
 293          in one of the available parity distribution methods.
 294
 295 config DM_LOG_USERSPACE
 296         tristate "Mirror userspace logging (EXPERIMENTAL)"
 297         depends on DM_MIRROR && EXPERIMENTAL && NET
 298         select CONNECTOR
 299         ---help---
 300           The userspace logging module provides a mechanism for
 301           relaying the dm-dirty-log API to userspace.  Log designs
 302           which are more suited to userspace implementation (e.g.
 303           shared storage logs) or experimental logs can be implemented
 304           by leveraging this framework.
 305
 306 config DM_ZERO
 307         tristate "Zero target"
 308         depends on BLK_DEV_DM
 309         ---help---
 310           A target that discards writes, and returns all zeroes for
 311           reads.  Useful in some recovery situations.
 312
 313 config DM_MULTIPATH
 314         tristate "Multipath target"
 315         depends on BLK_DEV_DM
 316         # nasty syntax but means make DM_MULTIPATH independent
 317         # of SCSI_DH if the latter isn't defined but if
 318         # it is, DM_MULTIPATH must depend on it.  We get a build
 319         # error if SCSI_DH=m and DM_MULTIPATH=y
 320         depends on SCSI_DH || !SCSI_DH
 321         ---help---
 322           Allow volume managers to support multipath hardware.
 323
 324 config DM_MULTIPATH_QL
 325         tristate "I/O Path Selector based on the number of in-flight I/Os"
 326         depends on DM_MULTIPATH
 327         ---help---
 328           This path selector is a dynamic load balancer which selects
 329           the path with the least number of in-flight I/Os.
 330
 331           If unsure, say N.
 332
 333 config DM_MULTIPATH_ST
 334         tristate "I/O Path Selector based on the service time"
 335         depends on DM_MULTIPATH
 336         ---help---
 337           This path selector is a dynamic load balancer which selects
 338           the path expected to complete the incoming I/O in the shortest
 339           time.
 340
 341           If unsure, say N.
 342
 343 config DM_DELAY
 344         tristate "I/O delaying target (EXPERIMENTAL)"
 345         depends on BLK_DEV_DM && EXPERIMENTAL
 346         ---help---
 347         A target that delays reads and/or writes and can send
 348         them to different devices.  Useful for testing.
 349
 350         If unsure, say N.
 351
 352 config DM_UEVENT
 353         bool "DM uevents"
 354         depends on BLK_DEV_DM
 355         ---help---
 356         Generate udev events for DM events.
 357
 358 config DM_FLAKEY
 359        tristate "Flakey target (EXPERIMENTAL)"
 360        depends on BLK_DEV_DM && EXPERIMENTAL
 361        ---help---
 362          A target that intermittently fails I/O for debugging purposes.
 363
 364 config DM_VERITY
 365         tristate "Verity target support (EXPERIMENTAL)"
 366         depends on BLK_DEV_DM && EXPERIMENTAL
 367         select CRYPTO
 368         select CRYPTO_HASH
 369         select DM_BUFIO
 370         ---help---
 371           This device-mapper target creates a read-only device that
 372           transparently validates the data on one underlying device against
 373           a pre-generated tree of cryptographic checksums stored on a second
 374           device.
 375
 376           You'll need to activate the digests you're going to use in the
 377           cryptoapi configuration.
 378
 379           To compile this code as a module, choose M here: the module will
 380           be called dm-verity.
 381
 382           If unsure, say N.
 383
 384 endif # MD