xref: /openbmc/linux/drivers/md/Kconfig (revision 14f50b49)
11da177e4SLinus Torvalds#
21da177e4SLinus Torvalds# Block device driver configuration
31da177e4SLinus Torvalds#
41da177e4SLinus Torvalds
59361401eSDavid Howellsif BLOCK
69361401eSDavid Howells
71da177e4SLinus Torvaldsmenu "Multi-device support (RAID and LVM)"
81da177e4SLinus Torvalds
91da177e4SLinus Torvaldsconfig MD
101da177e4SLinus Torvalds	bool "Multiple devices driver support (RAID and LVM)"
111da177e4SLinus Torvalds	help
121da177e4SLinus Torvalds	  Support multiple physical spindles through a single logical device.
131da177e4SLinus Torvalds	  Required for RAID and logical volume management.
141da177e4SLinus Torvalds
151da177e4SLinus Torvaldsconfig BLK_DEV_MD
161da177e4SLinus Torvalds	tristate "RAID support"
171da177e4SLinus Torvalds	depends on MD
181da177e4SLinus Torvalds	---help---
191da177e4SLinus Torvalds	  This driver lets you combine several hard disk partitions into one
201da177e4SLinus Torvalds	  logical block device. This can be used to simply append one
211da177e4SLinus Torvalds	  partition to another one or to combine several redundant hard disks
221da177e4SLinus Torvalds	  into a RAID1/4/5 device so as to provide protection against hard
231da177e4SLinus Torvalds	  disk failures. This is called "Software RAID" since the combining of
241da177e4SLinus Torvalds	  the partitions is done by the kernel. "Hardware RAID" means that the
251da177e4SLinus Torvalds	  combining is done by a dedicated controller; if you have such a
261da177e4SLinus Torvalds	  controller, you do not need to say Y here.
271da177e4SLinus Torvalds
281da177e4SLinus Torvalds	  More information about Software RAID on Linux is contained in the
291da177e4SLinus Torvalds	  Software RAID mini-HOWTO, available from
301da177e4SLinus Torvalds	  <http://www.tldp.org/docs.html#howto>. There you will also learn
311da177e4SLinus Torvalds	  where to get the supporting user space utilities raidtools.
321da177e4SLinus Torvalds
331da177e4SLinus Torvalds	  If unsure, say N.
341da177e4SLinus Torvalds
351da177e4SLinus Torvaldsconfig MD_LINEAR
361da177e4SLinus Torvalds	tristate "Linear (append) mode"
371da177e4SLinus Torvalds	depends on BLK_DEV_MD
381da177e4SLinus Torvalds	---help---
391da177e4SLinus Torvalds	  If you say Y here, then your multiple devices driver will be able to
401da177e4SLinus Torvalds	  use the so-called linear mode, i.e. it will combine the hard disk
411da177e4SLinus Torvalds	  partitions by simply appending one to the other.
421da177e4SLinus Torvalds
431da177e4SLinus Torvalds	  To compile this as a module, choose M here: the module
441da177e4SLinus Torvalds	  will be called linear.
451da177e4SLinus Torvalds
461da177e4SLinus Torvalds	  If unsure, say Y.
471da177e4SLinus Torvalds
481da177e4SLinus Torvaldsconfig MD_RAID0
491da177e4SLinus Torvalds	tristate "RAID-0 (striping) mode"
501da177e4SLinus Torvalds	depends on BLK_DEV_MD
511da177e4SLinus Torvalds	---help---
521da177e4SLinus Torvalds	  If you say Y here, then your multiple devices driver will be able to
531da177e4SLinus Torvalds	  use the so-called raid0 mode, i.e. it will combine the hard disk
541da177e4SLinus Torvalds	  partitions into one logical device in such a fashion as to fill them
551da177e4SLinus Torvalds	  up evenly, one chunk here and one chunk there. This will increase
561da177e4SLinus Torvalds	  the throughput rate if the partitions reside on distinct disks.
571da177e4SLinus Torvalds
581da177e4SLinus Torvalds	  Information about Software RAID on Linux is contained in the
591da177e4SLinus Torvalds	  Software-RAID mini-HOWTO, available from
601da177e4SLinus Torvalds	  <http://www.tldp.org/docs.html#howto>. There you will also
611da177e4SLinus Torvalds	  learn where to get the supporting user space utilities raidtools.
621da177e4SLinus Torvalds
631da177e4SLinus Torvalds	  To compile this as a module, choose M here: the module
641da177e4SLinus Torvalds	  will be called raid0.
651da177e4SLinus Torvalds
661da177e4SLinus Torvalds	  If unsure, say Y.
671da177e4SLinus Torvalds
681da177e4SLinus Torvaldsconfig MD_RAID1
691da177e4SLinus Torvalds	tristate "RAID-1 (mirroring) mode"
701da177e4SLinus Torvalds	depends on BLK_DEV_MD
711da177e4SLinus Torvalds	---help---
721da177e4SLinus Torvalds	  A RAID-1 set consists of several disk drives which are exact copies
731da177e4SLinus Torvalds	  of each other.  In the event of a mirror failure, the RAID driver
741da177e4SLinus Torvalds	  will continue to use the operational mirrors in the set, providing
751da177e4SLinus Torvalds	  an error free MD (multiple device) to the higher levels of the
761da177e4SLinus Torvalds	  kernel.  In a set with N drives, the available space is the capacity
771da177e4SLinus Torvalds	  of a single drive, and the set protects against a failure of (N - 1)
781da177e4SLinus Torvalds	  drives.
791da177e4SLinus Torvalds
801da177e4SLinus Torvalds	  Information about Software RAID on Linux is contained in the
811da177e4SLinus Torvalds	  Software-RAID mini-HOWTO, available from
821da177e4SLinus Torvalds	  <http://www.tldp.org/docs.html#howto>.  There you will also
831da177e4SLinus Torvalds	  learn where to get the supporting user space utilities raidtools.
841da177e4SLinus Torvalds
851da177e4SLinus Torvalds	  If you want to use such a RAID-1 set, say Y.  To compile this code
861da177e4SLinus Torvalds	  as a module, choose M here: the module will be called raid1.
871da177e4SLinus Torvalds
881da177e4SLinus Torvalds	  If unsure, say Y.
891da177e4SLinus Torvalds
901da177e4SLinus Torvaldsconfig MD_RAID10
911da177e4SLinus Torvalds	tristate "RAID-10 (mirrored striping) mode (EXPERIMENTAL)"
921da177e4SLinus Torvalds	depends on BLK_DEV_MD && EXPERIMENTAL
931da177e4SLinus Torvalds	---help---
941da177e4SLinus Torvalds	  RAID-10 provides a combination of striping (RAID-0) and
954d2554d0SJustin Piszcz	  mirroring (RAID-1) with easier configuration and more flexible
961da177e4SLinus Torvalds	  layout.
971da177e4SLinus Torvalds	  Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to
981da177e4SLinus Torvalds	  be the same size (or at least, only as much as the smallest device
991da177e4SLinus Torvalds	  will be used).
1001da177e4SLinus Torvalds	  RAID-10 provides a variety of layouts that provide different levels
1011da177e4SLinus Torvalds	  of redundancy and performance.
1021da177e4SLinus Torvalds
1031da177e4SLinus Torvalds	  RAID-10 requires mdadm-1.7.0 or later, available at:
1041da177e4SLinus Torvalds
1051da177e4SLinus Torvalds	  ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/
1061da177e4SLinus Torvalds
1071da177e4SLinus Torvalds	  If unsure, say Y.
1081da177e4SLinus Torvalds
10916a53eccSNeilBrownconfig MD_RAID456
11016a53eccSNeilBrown	tristate "RAID-4/RAID-5/RAID-6 mode"
1111da177e4SLinus Torvalds	depends on BLK_DEV_MD
1121da177e4SLinus Torvalds	---help---
1131da177e4SLinus Torvalds	  A RAID-5 set of N drives with a capacity of C MB per drive provides
1141da177e4SLinus Torvalds	  the capacity of C * (N - 1) MB, and protects against a failure
1151da177e4SLinus Torvalds	  of a single drive. For a given sector (row) number, (N - 1) drives
1161da177e4SLinus Torvalds	  contain data sectors, and one drive contains the parity protection.
1171da177e4SLinus Torvalds	  For a RAID-4 set, the parity blocks are present on a single drive,
1181da177e4SLinus Torvalds	  while a RAID-5 set distributes the parity across the drives in one
1191da177e4SLinus Torvalds	  of the available parity distribution methods.
1201da177e4SLinus Torvalds
12116a53eccSNeilBrown	  A RAID-6 set of N drives with a capacity of C MB per drive
12216a53eccSNeilBrown	  provides the capacity of C * (N - 2) MB, and protects
12316a53eccSNeilBrown	  against a failure of any two drives. For a given sector
12416a53eccSNeilBrown	  (row) number, (N - 2) drives contain data sectors, and two
12516a53eccSNeilBrown	  drives contains two independent redundancy syndromes.  Like
12616a53eccSNeilBrown	  RAID-5, RAID-6 distributes the syndromes across the drives
12716a53eccSNeilBrown	  in one of the available parity distribution methods.
12816a53eccSNeilBrown
1291da177e4SLinus Torvalds	  Information about Software RAID on Linux is contained in the
1301da177e4SLinus Torvalds	  Software-RAID mini-HOWTO, available from
1311da177e4SLinus Torvalds	  <http://www.tldp.org/docs.html#howto>. There you will also
1321da177e4SLinus Torvalds	  learn where to get the supporting user space utilities raidtools.
1331da177e4SLinus Torvalds
13416a53eccSNeilBrown	  If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y.  To
1351da177e4SLinus Torvalds	  compile this code as a module, choose M here: the module
13616a53eccSNeilBrown	  will be called raid456.
1371da177e4SLinus Torvalds
1381da177e4SLinus Torvalds	  If unsure, say Y.
1391da177e4SLinus Torvalds
14029269553SNeilBrownconfig MD_RAID5_RESHAPE
14114f50b49SNeilBrown	bool "Support adding drives to a raid-5 array"
14214f50b49SNeilBrown	depends on MD_RAID456
14314f50b49SNeilBrown	default y
14429269553SNeilBrown	---help---
14529269553SNeilBrown	  A RAID-5 set can be expanded by adding extra drives. This
14629269553SNeilBrown	  requires "restriping" the array which means (almost) every
14729269553SNeilBrown	  block must be written to a different place.
14829269553SNeilBrown
14929269553SNeilBrown          This option allows such restriping to be done while the array
15014f50b49SNeilBrown	  is online.
15129269553SNeilBrown
1524d2554d0SJustin Piszcz	  You will need mdadm version 2.4.1 or later to use this
1536f91fe88SNeilBrown	  feature safely.  During the early stage of reshape there is
1546f91fe88SNeilBrown	  a critical section where live data is being over-written.  A
1556f91fe88SNeilBrown	  crash during this time needs extra care for recovery.  The
1566f91fe88SNeilBrown	  newer mdadm takes a copy of the data in the critical section
1576f91fe88SNeilBrown	  and will restore it, if necessary, after a crash.
15829269553SNeilBrown
15929269553SNeilBrown	  The mdadm usage is e.g.
16029269553SNeilBrown	       mdadm --grow /dev/md1 --raid-disks=6
16129269553SNeilBrown	  to grow '/dev/md1' to having 6 disks.
16229269553SNeilBrown
16329269553SNeilBrown	  Note: The array can only be expanded, not contracted.
16429269553SNeilBrown	  There should be enough spares already present to make the new
16529269553SNeilBrown	  array workable.
16629269553SNeilBrown
16714f50b49SNeilBrown	  If unsure, say Y.
16814f50b49SNeilBrown
1691da177e4SLinus Torvaldsconfig MD_MULTIPATH
1701da177e4SLinus Torvalds	tristate "Multipath I/O support"
1711da177e4SLinus Torvalds	depends on BLK_DEV_MD
1721da177e4SLinus Torvalds	help
1731da177e4SLinus Torvalds	  Multipath-IO is the ability of certain devices to address the same
1741da177e4SLinus Torvalds	  physical disk over multiple 'IO paths'. The code ensures that such
1751da177e4SLinus Torvalds	  paths can be defined and handled at runtime, and ensures that a
1761da177e4SLinus Torvalds	  transparent failover to the backup path(s) happens if a IO errors
1771da177e4SLinus Torvalds	  arrives on the primary path.
1781da177e4SLinus Torvalds
1791da177e4SLinus Torvalds	  If unsure, say N.
1801da177e4SLinus Torvalds
1811da177e4SLinus Torvaldsconfig MD_FAULTY
1821da177e4SLinus Torvalds	tristate "Faulty test module for MD"
1831da177e4SLinus Torvalds	depends on BLK_DEV_MD
1841da177e4SLinus Torvalds	help
1851da177e4SLinus Torvalds	  The "faulty" module allows for a block device that occasionally returns
1861da177e4SLinus Torvalds	  read or write errors.  It is useful for testing.
1871da177e4SLinus Torvalds
1881da177e4SLinus Torvalds	  In unsure, say N.
1891da177e4SLinus Torvalds
1901da177e4SLinus Torvaldsconfig BLK_DEV_DM
1911da177e4SLinus Torvalds	tristate "Device mapper support"
1921da177e4SLinus Torvalds	depends on MD
1931da177e4SLinus Torvalds	---help---
1941da177e4SLinus Torvalds	  Device-mapper is a low level volume manager.  It works by allowing
1951da177e4SLinus Torvalds	  people to specify mappings for ranges of logical sectors.  Various
1961da177e4SLinus Torvalds	  mapping types are available, in addition people may write their own
1971da177e4SLinus Torvalds	  modules containing custom mappings if they wish.
1981da177e4SLinus Torvalds
1991da177e4SLinus Torvalds	  Higher level volume managers such as LVM2 use this driver.
2001da177e4SLinus Torvalds
2011da177e4SLinus Torvalds	  To compile this as a module, choose M here: the module will be
2021da177e4SLinus Torvalds	  called dm-mod.
2031da177e4SLinus Torvalds
2041da177e4SLinus Torvalds	  If unsure, say N.
2051da177e4SLinus Torvalds
206cc109201SBryn Reevesconfig DM_DEBUG
207cc109201SBryn Reeves	boolean "Device mapper debugging support"
208cc109201SBryn Reeves	depends on BLK_DEV_DM && EXPERIMENTAL
209cc109201SBryn Reeves	---help---
210cc109201SBryn Reeves	  Enable this for messages that may help debug device-mapper problems.
211cc109201SBryn Reeves
212cc109201SBryn Reeves	  If unsure, say N.
213cc109201SBryn Reeves
2141da177e4SLinus Torvaldsconfig DM_CRYPT
2151da177e4SLinus Torvalds	tristate "Crypt target support"
2161da177e4SLinus Torvalds	depends on BLK_DEV_DM && EXPERIMENTAL
2171da177e4SLinus Torvalds	select CRYPTO
2181da177e4SLinus Torvalds	---help---
2191da177e4SLinus Torvalds	  This device-mapper target allows you to create a device that
2201da177e4SLinus Torvalds	  transparently encrypts the data on it. You'll need to activate
2211da177e4SLinus Torvalds	  the ciphers you're going to use in the cryptoapi configuration.
2221da177e4SLinus Torvalds
2231da177e4SLinus Torvalds	  Information on how to use dm-crypt can be found on
2241da177e4SLinus Torvalds
2251da177e4SLinus Torvalds	  <http://www.saout.de/misc/dm-crypt/>
2261da177e4SLinus Torvalds
2271da177e4SLinus Torvalds	  To compile this code as a module, choose M here: the module will
2281da177e4SLinus Torvalds	  be called dm-crypt.
2291da177e4SLinus Torvalds
2301da177e4SLinus Torvalds	  If unsure, say N.
2311da177e4SLinus Torvalds
2321da177e4SLinus Torvaldsconfig DM_SNAPSHOT
2331da177e4SLinus Torvalds       tristate "Snapshot target (EXPERIMENTAL)"
2341da177e4SLinus Torvalds       depends on BLK_DEV_DM && EXPERIMENTAL
2351da177e4SLinus Torvalds       ---help---
2364d2554d0SJustin Piszcz         Allow volume managers to take writable snapshots of a device.
2371da177e4SLinus Torvalds
2381da177e4SLinus Torvaldsconfig DM_MIRROR
2391da177e4SLinus Torvalds       tristate "Mirror target (EXPERIMENTAL)"
2401da177e4SLinus Torvalds       depends on BLK_DEV_DM && EXPERIMENTAL
2411da177e4SLinus Torvalds       ---help---
2421da177e4SLinus Torvalds         Allow volume managers to mirror logical volumes, also
2431da177e4SLinus Torvalds         needed for live data migration tools such as 'pvmove'.
2441da177e4SLinus Torvalds
2451da177e4SLinus Torvaldsconfig DM_ZERO
2461da177e4SLinus Torvalds	tristate "Zero target (EXPERIMENTAL)"
2471da177e4SLinus Torvalds	depends on BLK_DEV_DM && EXPERIMENTAL
2481da177e4SLinus Torvalds	---help---
2491da177e4SLinus Torvalds	  A target that discards writes, and returns all zeroes for
2501da177e4SLinus Torvalds	  reads.  Useful in some recovery situations.
2511da177e4SLinus Torvalds
2521da177e4SLinus Torvaldsconfig DM_MULTIPATH
2531da177e4SLinus Torvalds	tristate "Multipath target (EXPERIMENTAL)"
2541da177e4SLinus Torvalds	depends on BLK_DEV_DM && EXPERIMENTAL
2551da177e4SLinus Torvalds	---help---
2561da177e4SLinus Torvalds	  Allow volume managers to support multipath hardware.
2571da177e4SLinus Torvalds
2581da177e4SLinus Torvaldsconfig DM_MULTIPATH_EMC
2591da177e4SLinus Torvalds	tristate "EMC CX/AX multipath support (EXPERIMENTAL)"
2601da177e4SLinus Torvalds	depends on DM_MULTIPATH && BLK_DEV_DM && EXPERIMENTAL
2611da177e4SLinus Torvalds	---help---
2621da177e4SLinus Torvalds	  Multipath support for EMC CX/AX series hardware.
2631da177e4SLinus Torvalds
2641da177e4SLinus Torvaldsendmenu
2651da177e4SLinus Torvalds
2669361401eSDavid Howellsendif
267