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 (EXPERIMENTAL)"
 104         depends on BLK_DEV_MD && EXPERIMENTAL
 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 MD_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_RAID6_PQ
 169         tristate
 170
 171 config ASYNC_RAID6_TEST
 172         tristate "Self test for hardware accelerated raid6 recovery"
 173         depends on MD_RAID6_PQ
 174         select ASYNC_RAID6_RECOV
 175         ---help---
 176           This is a one-shot self test that permutes through the
 177           recovery of all the possible two disk failure scenarios for a
 178           N-disk array.  Recovery is performed with the asynchronous
 179           raid6 recovery routines, and will optionally use an offload
 180           engine if one is available.
 181
 182           If unsure, say N.
 183
 184 config MD_MULTIPATH
 185         tristate "Multipath I/O support"
 186         depends on BLK_DEV_MD
 187         help
 188           MD_MULTIPATH provides a simple multi-path personality for use
 189           the MD framework.  It is not under active development.  New
 190           projects should consider using DM_MULTIPATH which has more
 191           features and more testing.
 192
 193           If unsure, say N.
 194
 195 config MD_FAULTY
 196         tristate "Faulty test module for MD"
 197         depends on BLK_DEV_MD
 198         help
 199           The "faulty" module allows for a block device that occasionally returns
 200           read or write errors.  It is useful for testing.
 201
 202           In unsure, say N.
 203
 204 config BLK_DEV_DM
 205         tristate "Device mapper support"
 206         ---help---
 207           Device-mapper is a low level volume manager.  It works by allowing
 208           people to specify mappings for ranges of logical sectors.  Various
 209           mapping types are available, in addition people may write their own
 210           modules containing custom mappings if they wish.
 211
 212           Higher level volume managers such as LVM2 use this driver.
 213
 214           To compile this as a module, choose M here: the module will be
 215           called dm-mod.
 216
 217           If unsure, say N.
 218
 219 config DM_DEBUG
 220         boolean "Device mapper debugging support"
 221         depends on BLK_DEV_DM
 222         ---help---
 223           Enable this for messages that may help debug device-mapper problems.
 224
 225           If unsure, say N.
 226
 227 config DM_CRYPT
 228         tristate "Crypt target support"
 229         depends on BLK_DEV_DM
 230         select CRYPTO
 231         select CRYPTO_CBC
 232         ---help---
 233           This device-mapper target allows you to create a device that
 234           transparently encrypts the data on it. You'll need to activate
 235           the ciphers you're going to use in the cryptoapi configuration.
 236
 237           Information on how to use dm-crypt can be found on
 238
 239           <http://www.saout.de/misc/dm-crypt/>
 240
 241           To compile this code as a module, choose M here: the module will
 242           be called dm-crypt.
 243
 244           If unsure, say N.
 245
 246 config DM_SNAPSHOT
 247        tristate "Snapshot target"
 248        depends on BLK_DEV_DM
 249        ---help---
 250          Allow volume managers to take writable snapshots of a device.
 251
 252 config DM_MIRROR
 253        tristate "Mirror target"
 254        depends on BLK_DEV_DM
 255        ---help---
 256          Allow volume managers to mirror logical volumes, also
 257          needed for live data migration tools such as 'pvmove'.
 258
 259 config DM_LOG_USERSPACE
 260         tristate "Mirror userspace logging (EXPERIMENTAL)"
 261         depends on DM_MIRROR && EXPERIMENTAL && NET
 262         select CONNECTOR
 263         ---help---
 264           The userspace logging module provides a mechanism for
 265           relaying the dm-dirty-log API to userspace.  Log designs
 266           which are more suited to userspace implementation (e.g.
 267           shared storage logs) or experimental logs can be implemented
 268           by leveraging this framework.
 269
 270 config DM_ZERO
 271         tristate "Zero target"
 272         depends on BLK_DEV_DM
 273         ---help---
 274           A target that discards writes, and returns all zeroes for
 275           reads.  Useful in some recovery situations.
 276
 277 config DM_MULTIPATH
 278         tristate "Multipath target"
 279         depends on BLK_DEV_DM
 280         # nasty syntax but means make DM_MULTIPATH independent
 281         # of SCSI_DH if the latter isn't defined but if
 282         # it is, DM_MULTIPATH must depend on it.  We get a build
 283         # error if SCSI_DH=m and DM_MULTIPATH=y
 284         depends on SCSI_DH || !SCSI_DH
 285         ---help---
 286           Allow volume managers to support multipath hardware.
 287
 288 config DM_MULTIPATH_QL
 289         tristate "I/O Path Selector based on the number of in-flight I/Os"
 290         depends on DM_MULTIPATH
 291         ---help---
 292           This path selector is a dynamic load balancer which selects
 293           the path with the least number of in-flight I/Os.
 294
 295           If unsure, say N.
 296
 297 config DM_MULTIPATH_ST
 298         tristate "I/O Path Selector based on the service time"
 299         depends on DM_MULTIPATH
 300         ---help---
 301           This path selector is a dynamic load balancer which selects
 302           the path expected to complete the incoming I/O in the shortest
 303           time.
 304
 305           If unsure, say N.
 306
 307 config DM_DELAY
 308         tristate "I/O delaying target (EXPERIMENTAL)"
 309         depends on BLK_DEV_DM && EXPERIMENTAL
 310         ---help---
 311         A target that delays reads and/or writes and can send
 312         them to different devices.  Useful for testing.
 313
 314         If unsure, say N.
 315
 316 config DM_UEVENT
 317         bool "DM uevents (EXPERIMENTAL)"
 318         depends on BLK_DEV_DM && EXPERIMENTAL
 319         ---help---
 320         Generate udev events for DM events.
 321
 322 endif # MD