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_CRYPT
 212         tristate "Crypt target support"
 213         depends on BLK_DEV_DM
 214         select CRYPTO
 215         select CRYPTO_CBC
 216         ---help---
 217           This device-mapper target allows you to create a device that
 218           transparently encrypts the data on it. You'll need to activate
 219           the ciphers you're going to use in the cryptoapi configuration.
 220
 221           Information on how to use dm-crypt can be found on
 222
 223           <http://www.saout.de/misc/dm-crypt/>
 224
 225           To compile this code as a module, choose M here: the module will
 226           be called dm-crypt.
 227
 228           If unsure, say N.
 229
 230 config DM_SNAPSHOT
 231        tristate "Snapshot target"
 232        depends on BLK_DEV_DM
 233        ---help---
 234          Allow volume managers to take writable snapshots of a device.
 235
 236 config DM_MIRROR
 237        tristate "Mirror target"
 238        depends on BLK_DEV_DM
 239        ---help---
 240          Allow volume managers to mirror logical volumes, also
 241          needed for live data migration tools such as 'pvmove'.
 242
 243 config DM_RAID
 244        tristate "RAID 1/4/5/6 target (EXPERIMENTAL)"
 245        depends on BLK_DEV_DM && EXPERIMENTAL
 246        select MD_RAID1
 247        select MD_RAID456
 248        select BLK_DEV_MD
 249        ---help---
 250          A dm target that supports RAID1, RAID4, RAID5 and RAID6 mappings
 251
 252          A RAID-5 set of N drives with a capacity of C MB per drive provides
 253          the capacity of C * (N - 1) MB, and protects against a failure
 254          of a single drive. For a given sector (row) number, (N - 1) drives
 255          contain data sectors, and one drive contains the parity protection.
 256          For a RAID-4 set, the parity blocks are present on a single drive,
 257          while a RAID-5 set distributes the parity across the drives in one
 258          of the available parity distribution methods.
 259
 260          A RAID-6 set of N drives with a capacity of C MB per drive
 261          provides the capacity of C * (N - 2) MB, and protects
 262          against a failure of any two drives. For a given sector
 263          (row) number, (N - 2) drives contain data sectors, and two
 264          drives contains two independent redundancy syndromes.  Like
 265          RAID-5, RAID-6 distributes the syndromes across the drives
 266          in one of the available parity distribution methods.
 267
 268 config DM_LOG_USERSPACE
 269         tristate "Mirror userspace logging (EXPERIMENTAL)"
 270         depends on DM_MIRROR && EXPERIMENTAL && NET
 271         select CONNECTOR
 272         ---help---
 273           The userspace logging module provides a mechanism for
 274           relaying the dm-dirty-log API to userspace.  Log designs
 275           which are more suited to userspace implementation (e.g.
 276           shared storage logs) or experimental logs can be implemented
 277           by leveraging this framework.
 278
 279 config DM_ZERO
 280         tristate "Zero target"
 281         depends on BLK_DEV_DM
 282         ---help---
 283           A target that discards writes, and returns all zeroes for
 284           reads.  Useful in some recovery situations.
 285
 286 config DM_MULTIPATH
 287         tristate "Multipath target"
 288         depends on BLK_DEV_DM
 289         # nasty syntax but means make DM_MULTIPATH independent
 290         # of SCSI_DH if the latter isn't defined but if
 291         # it is, DM_MULTIPATH must depend on it.  We get a build
 292         # error if SCSI_DH=m and DM_MULTIPATH=y
 293         depends on SCSI_DH || !SCSI_DH
 294         ---help---
 295           Allow volume managers to support multipath hardware.
 296
 297 config DM_MULTIPATH_QL
 298         tristate "I/O Path Selector based on the number of in-flight I/Os"
 299         depends on DM_MULTIPATH
 300         ---help---
 301           This path selector is a dynamic load balancer which selects
 302           the path with the least number of in-flight I/Os.
 303
 304           If unsure, say N.
 305
 306 config DM_MULTIPATH_ST
 307         tristate "I/O Path Selector based on the service time"
 308         depends on DM_MULTIPATH
 309         ---help---
 310           This path selector is a dynamic load balancer which selects
 311           the path expected to complete the incoming I/O in the shortest
 312           time.
 313
 314           If unsure, say N.
 315
 316 config DM_DELAY
 317         tristate "I/O delaying target (EXPERIMENTAL)"
 318         depends on BLK_DEV_DM && EXPERIMENTAL
 319         ---help---
 320         A target that delays reads and/or writes and can send
 321         them to different devices.  Useful for testing.
 322
 323         If unsure, say N.
 324
 325 config DM_UEVENT
 326         bool "DM uevents (EXPERIMENTAL)"
 327         depends on BLK_DEV_DM && EXPERIMENTAL
 328         ---help---
 329         Generate udev events for DM events.
 330
 331 config DM_FLAKEY
 332        tristate "Flakey target (EXPERIMENTAL)"
 333        depends on BLK_DEV_DM && EXPERIMENTAL
 334        ---help---
 335          A target that intermittently fails I/O for debugging purposes.
 336
 337 endif # MD