drivers/md/Kconfig - linux - Git at Google


            
            #

            
            # Block device driver configuration

            
            #


            menuconfig MD

            
            	bool "Multiple devices driver support (RAID and LVM)"

            
            	depends on BLOCK

            
            	help

            
            	  Support multiple physical spindles through a single logical device.

            
            	  Required for RAID and logical volume management.


            if MD


            config BLK_DEV_MD

            
            	tristate "RAID support"

            
            	---help---

            
            	  This driver lets you combine several hard disk partitions into one

            
            	  logical block device. This can be used to simply append one

            
            	  partition to another one or to combine several redundant hard disks

            
            	  into a RAID1/4/5 device so as to provide protection against hard

            
            	  disk failures. This is called "Software RAID" since the combining of

            
            	  the partitions is done by the kernel. "Hardware RAID" means that the

            
            	  combining is done by a dedicated controller; if you have such a

            
            	  controller, you do not need to say Y here.


            	  More information about Software RAID on Linux is contained in the

            
            	  Software RAID mini-HOWTO, available from

            
            	  <http://www.tldp.org/docs.html#howto>. There you will also learn

            
            	  where to get the supporting user space utilities raidtools.


            	  If unsure, say N.


            config MD_AUTODETECT

            
            	bool "Autodetect RAID arrays during kernel boot"

            
            	depends on BLK_DEV_MD=y

            
            	default y

            
            	---help---

            
            	  If you say Y here, then the kernel will try to autodetect raid

            
            	  arrays as part of its boot process.


            	  If you don't use raid and say Y, this autodetection can cause

            
            	  a several-second delay in the boot time due to various

            
            	  synchronisation steps that are part of this step.


            	  If unsure, say Y.


            config MD_LINEAR

            
            	tristate "Linear (append) mode"

            
            	depends on BLK_DEV_MD

            
            	---help---

            
            	  If you say Y here, then your multiple devices driver will be able to

            
            	  use the so-called linear mode, i.e. it will combine the hard disk

            
            	  partitions by simply appending one to the other.


            	  To compile this as a module, choose M here: the module

            
            	  will be called linear.


            	  If unsure, say Y.


            config MD_RAID0

            
            	tristate "RAID-0 (striping) mode"

            
            	depends on BLK_DEV_MD

            
            	---help---

            
            	  If you say Y here, then your multiple devices driver will be able to

            
            	  use the so-called raid0 mode, i.e. it will combine the hard disk

            
            	  partitions into one logical device in such a fashion as to fill them

            
            	  up evenly, one chunk here and one chunk there. This will increase

            
            	  the throughput rate if the partitions reside on distinct disks.


            	  Information about Software RAID on Linux is contained in the

            
            	  Software-RAID mini-HOWTO, available from

            
            	  <http://www.tldp.org/docs.html#howto>. There you will also

            
            	  learn where to get the supporting user space utilities raidtools.


            	  To compile this as a module, choose M here: the module

            
            	  will be called raid0.


            	  If unsure, say Y.


            config MD_RAID1

            
            	tristate "RAID-1 (mirroring) mode"

            
            	depends on BLK_DEV_MD

            
            	---help---

            
            	  A RAID-1 set consists of several disk drives which are exact copies

            
            	  of each other.  In the event of a mirror failure, the RAID driver

            
            	  will continue to use the operational mirrors in the set, providing

            
            	  an error free MD (multiple device) to the higher levels of the

            
            	  kernel.  In a set with N drives, the available space is the capacity

            
            	  of a single drive, and the set protects against a failure of (N - 1)

            
            	  drives.


            	  Information about Software RAID on Linux is contained in the

            
            	  Software-RAID mini-HOWTO, available from

            
            	  <http://www.tldp.org/docs.html#howto>.  There you will also

            
            	  learn where to get the supporting user space utilities raidtools.


            	  If you want to use such a RAID-1 set, say Y.  To compile this code

            
            	  as a module, choose M here: the module will be called raid1.


            	  If unsure, say Y.


            config MD_RAID10

            
            	tristate "RAID-10 (mirrored striping) mode (EXPERIMENTAL)"

            
            	depends on BLK_DEV_MD && EXPERIMENTAL

            
            	---help---

            
            	  RAID-10 provides a combination of striping (RAID-0) and

            
            	  mirroring (RAID-1) with easier configuration and more flexible

            
            	  layout.

            
            	  Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to

            
            	  be the same size (or at least, only as much as the smallest device

            
            	  will be used).

            
            	  RAID-10 provides a variety of layouts that provide different levels

            
            	  of redundancy and performance.


            	  RAID-10 requires mdadm-1.7.0 or later, available at:


            	  ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/


            	  If unsure, say Y.


            config MD_RAID456

            
            	tristate "RAID-4/RAID-5/RAID-6 mode"

            
            	depends on BLK_DEV_MD

            
            	select MD_RAID6_PQ

            
            	select ASYNC_MEMCPY

            
            	select ASYNC_XOR

            
            	---help---

            
            	  A RAID-5 set of N drives with a capacity of C MB per drive provides

            
            	  the capacity of C * (N - 1) MB, and protects against a failure

            
            	  of a single drive. For a given sector (row) number, (N - 1) drives

            
            	  contain data sectors, and one drive contains the parity protection.

            
            	  For a RAID-4 set, the parity blocks are present on a single drive,

            
            	  while a RAID-5 set distributes the parity across the drives in one

            
            	  of the available parity distribution methods.


            	  A RAID-6 set of N drives with a capacity of C MB per drive

            
            	  provides the capacity of C * (N - 2) MB, and protects

            
            	  against a failure of any two drives. For a given sector

            
            	  (row) number, (N - 2) drives contain data sectors, and two

            
            	  drives contains two independent redundancy syndromes.  Like

            
            	  RAID-5, RAID-6 distributes the syndromes across the drives

            
            	  in one of the available parity distribution methods.


            	  Information about Software RAID on Linux is contained in the

            
            	  Software-RAID mini-HOWTO, available from

            
            	  <http://www.tldp.org/docs.html#howto>. There you will also

            
            	  learn where to get the supporting user space utilities raidtools.


            	  If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y.  To

            
            	  compile this code as a module, choose M here: the module

            
            	  will be called raid456.


            	  If unsure, say Y.


            config MD_RAID6_PQ

            
            	tristate


            config MD_MULTIPATH

            
            	tristate "Multipath I/O support"

            
            	depends on BLK_DEV_MD

            
            	help

            
            	  Multipath-IO is the ability of certain devices to address the same

            
            	  physical disk over multiple 'IO paths'. The code ensures that such

            
            	  paths can be defined and handled at runtime, and ensures that a

            
            	  transparent failover to the backup path(s) happens if a IO errors

            
            	  arrives on the primary path.


            	  If unsure, say N.


            config MD_FAULTY

            
            	tristate "Faulty test module for MD"

            
            	depends on BLK_DEV_MD

            
            	help

            
            	  The "faulty" module allows for a block device that occasionally returns

            
            	  read or write errors.  It is useful for testing.


            	  In unsure, say N.


            config BLK_DEV_DM

            
            	tristate "Device mapper support"

            
            	---help---

            
            	  Device-mapper is a low level volume manager.  It works by allowing

            
            	  people to specify mappings for ranges of logical sectors.  Various

            
            	  mapping types are available, in addition people may write their own

            
            	  modules containing custom mappings if they wish.


            	  Higher level volume managers such as LVM2 use this driver.


            	  To compile this as a module, choose M here: the module will be

            
            	  called dm-mod.


            	  If unsure, say N.


            config DM_DEBUG

            
            	boolean "Device mapper debugging support"

            
            	depends on BLK_DEV_DM

            
            	---help---

            
            	  Enable this for messages that may help debug device-mapper problems.


            	  If unsure, say N.


            config DM_CRYPT

            
            	tristate "Crypt target support"

            
            	depends on BLK_DEV_DM

            
            	select CRYPTO

            
            	select CRYPTO_CBC

            
            	---help---

            
            	  This device-mapper target allows you to create a device that

            
            	  transparently encrypts the data on it. You'll need to activate

            
            	  the ciphers you're going to use in the cryptoapi configuration.


            	  Information on how to use dm-crypt can be found on


            	  <http://www.saout.de/misc/dm-crypt/>


            	  To compile this code as a module, choose M here: the module will

            
            	  be called dm-crypt.


            	  If unsure, say N.


            config DM_SNAPSHOT

            
                   tristate "Snapshot target"

            
                   depends on BLK_DEV_DM

            
                   ---help---

            
                     Allow volume managers to take writable snapshots of a device.


            config DM_MIRROR

            
                   tristate "Mirror target"

            
                   depends on BLK_DEV_DM

            
                   ---help---

            
                     Allow volume managers to mirror logical volumes, also

            
                     needed for live data migration tools such as 'pvmove'.


            config DM_ZERO

            
            	tristate "Zero target"

            
            	depends on BLK_DEV_DM

            
            	---help---

            
            	  A target that discards writes, and returns all zeroes for

            
            	  reads.  Useful in some recovery situations.


            config DM_MULTIPATH

            
            	tristate "Multipath target"

            
            	depends on BLK_DEV_DM

            
            	# nasty syntax but means make DM_MULTIPATH independent

            
            	# of SCSI_DH if the latter isn't defined but if

            
            	# it is, DM_MULTIPATH must depend on it.  We get a build

            
            	# error if SCSI_DH=m and DM_MULTIPATH=y

            
            	depends on SCSI_DH || !SCSI_DH

            
            	---help---

            
            	  Allow volume managers to support multipath hardware.


            config DM_DELAY

            
            	tristate "I/O delaying target (EXPERIMENTAL)"

            
            	depends on BLK_DEV_DM && EXPERIMENTAL

            
            	---help---

            
            	A target that delays reads and/or writes and can send

            
            	them to different devices.  Useful for testing.


            	If unsure, say N.


            config DM_UEVENT

            
            	bool "DM uevents (EXPERIMENTAL)"

            
            	depends on BLK_DEV_DM && EXPERIMENTAL

            
            	---help---

            
            	Generate udev events for DM events.


            endif # MD
	#
	# Block device driver configuration
	#

	menuconfig MD
	bool "Multiple devices driver support (RAID and LVM)"
	depends on BLOCK
	help
	Support multiple physical spindles through a single logical device.
	Required for RAID and logical volume management.

	if MD

	config BLK_DEV_MD
	tristate "RAID support"
	---help---
	This driver lets you combine several hard disk partitions into one
	logical block device. This can be used to simply append one
	partition to another one or to combine several redundant hard disks
	into a RAID1/4/5 device so as to provide protection against hard
	disk failures. This is called "Software RAID" since the combining of
	the partitions is done by the kernel. "Hardware RAID" means that the
	combining is done by a dedicated controller; if you have such a
	controller, you do not need to say Y here.

	More information about Software RAID on Linux is contained in the
	Software RAID mini-HOWTO, available from
	<http://www.tldp.org/docs.html#howto>. There you will also learn
	where to get the supporting user space utilities raidtools.

	If unsure, say N.

	config MD_AUTODETECT
	bool "Autodetect RAID arrays during kernel boot"
	depends on BLK_DEV_MD=y
	default y
	---help---
	If you say Y here, then the kernel will try to autodetect raid
	arrays as part of its boot process.

	If you don't use raid and say Y, this autodetection can cause
	a several-second delay in the boot time due to various
	synchronisation steps that are part of this step.

	If unsure, say Y.

	config MD_LINEAR
	tristate "Linear (append) mode"
	depends on BLK_DEV_MD
	---help---
	If you say Y here, then your multiple devices driver will be able to
	use the so-called linear mode, i.e. it will combine the hard disk
	partitions by simply appending one to the other.

	To compile this as a module, choose M here: the module
	will be called linear.

	If unsure, say Y.

	config MD_RAID0
	tristate "RAID-0 (striping) mode"
	depends on BLK_DEV_MD
	---help---
	If you say Y here, then your multiple devices driver will be able to
	use the so-called raid0 mode, i.e. it will combine the hard disk
	partitions into one logical device in such a fashion as to fill them
	up evenly, one chunk here and one chunk there. This will increase
	the throughput rate if the partitions reside on distinct disks.

	Information about Software RAID on Linux is contained in the
	Software-RAID mini-HOWTO, available from
	<http://www.tldp.org/docs.html#howto>. There you will also
	learn where to get the supporting user space utilities raidtools.

	To compile this as a module, choose M here: the module
	will be called raid0.

	If unsure, say Y.

	config MD_RAID1
	tristate "RAID-1 (mirroring) mode"
	depends on BLK_DEV_MD
	---help---
	A RAID-1 set consists of several disk drives which are exact copies
	of each other. In the event of a mirror failure, the RAID driver
	will continue to use the operational mirrors in the set, providing
	an error free MD (multiple device) to the higher levels of the
	kernel. In a set with N drives, the available space is the capacity
	of a single drive, and the set protects against a failure of (N - 1)
	drives.

	Information about Software RAID on Linux is contained in the
	Software-RAID mini-HOWTO, available from
	<http://www.tldp.org/docs.html#howto>. There you will also
	learn where to get the supporting user space utilities raidtools.

	If you want to use such a RAID-1 set, say Y. To compile this code
	as a module, choose M here: the module will be called raid1.

	If unsure, say Y.

	config MD_RAID10
	tristate "RAID-10 (mirrored striping) mode (EXPERIMENTAL)"
	depends on BLK_DEV_MD && EXPERIMENTAL
	---help---
	RAID-10 provides a combination of striping (RAID-0) and
	mirroring (RAID-1) with easier configuration and more flexible
	layout.
	Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to
	be the same size (or at least, only as much as the smallest device
	will be used).
	RAID-10 provides a variety of layouts that provide different levels
	of redundancy and performance.

	RAID-10 requires mdadm-1.7.0 or later, available at:

	ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/

	If unsure, say Y.

	config MD_RAID456
	tristate "RAID-4/RAID-5/RAID-6 mode"
	depends on BLK_DEV_MD
	select MD_RAID6_PQ
	select ASYNC_MEMCPY
	select ASYNC_XOR
	---help---
	A RAID-5 set of N drives with a capacity of C MB per drive provides
	the capacity of C * (N - 1) MB, and protects against a failure
	of a single drive. For a given sector (row) number, (N - 1) drives
	contain data sectors, and one drive contains the parity protection.
	For a RAID-4 set, the parity blocks are present on a single drive,
	while a RAID-5 set distributes the parity across the drives in one
	of the available parity distribution methods.

	A RAID-6 set of N drives with a capacity of C MB per drive
	provides the capacity of C * (N - 2) MB, and protects
	against a failure of any two drives. For a given sector
	(row) number, (N - 2) drives contain data sectors, and two
	drives contains two independent redundancy syndromes. Like
	RAID-5, RAID-6 distributes the syndromes across the drives
	in one of the available parity distribution methods.

	Information about Software RAID on Linux is contained in the
	Software-RAID mini-HOWTO, available from
	<http://www.tldp.org/docs.html#howto>. There you will also
	learn where to get the supporting user space utilities raidtools.

	If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To
	compile this code as a module, choose M here: the module
	will be called raid456.

	If unsure, say Y.

	config MD_RAID6_PQ
	tristate

	config MD_MULTIPATH
	tristate "Multipath I/O support"
	depends on BLK_DEV_MD
	help
	Multipath-IO is the ability of certain devices to address the same
	physical disk over multiple 'IO paths'. The code ensures that such
	paths can be defined and handled at runtime, and ensures that a
	transparent failover to the backup path(s) happens if a IO errors
	arrives on the primary path.

	If unsure, say N.

	config MD_FAULTY
	tristate "Faulty test module for MD"
	depends on BLK_DEV_MD
	help
	The "faulty" module allows for a block device that occasionally returns
	read or write errors. It is useful for testing.

	In unsure, say N.

	config BLK_DEV_DM
	tristate "Device mapper support"
	---help---
	Device-mapper is a low level volume manager. It works by allowing
	people to specify mappings for ranges of logical sectors. Various
	mapping types are available, in addition people may write their own
	modules containing custom mappings if they wish.

	Higher level volume managers such as LVM2 use this driver.

	To compile this as a module, choose M here: the module will be
	called dm-mod.

	If unsure, say N.

	config DM_DEBUG
	boolean "Device mapper debugging support"
	depends on BLK_DEV_DM
	---help---
	Enable this for messages that may help debug device-mapper problems.

	If unsure, say N.

	config DM_CRYPT
	tristate "Crypt target support"
	depends on BLK_DEV_DM
	select CRYPTO
	select CRYPTO_CBC
	---help---
	This device-mapper target allows you to create a device that
	transparently encrypts the data on it. You'll need to activate
	the ciphers you're going to use in the cryptoapi configuration.

	Information on how to use dm-crypt can be found on

	<http://www.saout.de/misc/dm-crypt/>

	To compile this code as a module, choose M here: the module will
	be called dm-crypt.

	If unsure, say N.

	config DM_SNAPSHOT
	tristate "Snapshot target"
	depends on BLK_DEV_DM
	---help---
	Allow volume managers to take writable snapshots of a device.

	config DM_MIRROR
	tristate "Mirror target"
	depends on BLK_DEV_DM
	---help---
	Allow volume managers to mirror logical volumes, also
	needed for live data migration tools such as 'pvmove'.

	config DM_ZERO
	tristate "Zero target"
	depends on BLK_DEV_DM
	---help---
	A target that discards writes, and returns all zeroes for
	reads. Useful in some recovery situations.

	config DM_MULTIPATH
	tristate "Multipath target"
	depends on BLK_DEV_DM
	# nasty syntax but means make DM_MULTIPATH independent
	# of SCSI_DH if the latter isn't defined but if
	# it is, DM_MULTIPATH must depend on it. We get a build
	# error if SCSI_DH=m and DM_MULTIPATH=y
	depends on SCSI_DH \|\| !SCSI_DH
	---help---
	Allow volume managers to support multipath hardware.

	config DM_DELAY
	tristate "I/O delaying target (EXPERIMENTAL)"
	depends on BLK_DEV_DM && EXPERIMENTAL
	---help---
	A target that delays reads and/or writes and can send
	them to different devices. Useful for testing.

	If unsure, say N.

	config DM_UEVENT
	bool "DM uevents (EXPERIMENTAL)"
	depends on BLK_DEV_DM && EXPERIMENTAL
	---help---
	Generate udev events for DM events.

	endif # MD