[linux-block.git] / drivers / md / Kconfig

#
# Block device driver configuration
#

if BLOCK

menu "Multi-device support (RAID and LVM)"

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

config BLK_DEV_MD
	tristate "RAID support"
	depends on MD
	---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_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 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_RAID5_RESHAPE
	bool "Support adding drives to a raid-5 array"
	depends on MD_RAID456
	default y
	---help---
	  A RAID-5 set can be expanded by adding extra drives. This
	  requires "restriping" the array which means (almost) every
	  block must be written to a different place.

          This option allows such restriping to be done while the array
	  is online.

	  You will need mdadm version 2.4.1 or later to use this
	  feature safely.  During the early stage of reshape there is
	  a critical section where live data is being over-written.  A
	  crash during this time needs extra care for recovery.  The
	  newer mdadm takes a copy of the data in the critical section
	  and will restore it, if necessary, after a crash.

	  The mdadm usage is e.g.
	       mdadm --grow /dev/md1 --raid-disks=6
	  to grow '/dev/md1' to having 6 disks.

	  Note: The array can only be expanded, not contracted.
	  There should be enough spares already present to make the new
	  array workable.

	  If unsure, say Y.

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"
	depends on MD
	---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 && EXPERIMENTAL
	---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 && EXPERIMENTAL
	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 (EXPERIMENTAL)"
       depends on BLK_DEV_DM && EXPERIMENTAL
       ---help---
         Allow volume managers to take writable snapshots of a device.

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

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

config DM_MULTIPATH
	tristate "Multipath target (EXPERIMENTAL)"
	depends on BLK_DEV_DM && EXPERIMENTAL
	---help---
	  Allow volume managers to support multipath hardware.

config DM_MULTIPATH_EMC
	tristate "EMC CX/AX multipath support (EXPERIMENTAL)"
	depends on DM_MULTIPATH && BLK_DEV_DM && EXPERIMENTAL
	---help---
	  Multipath support for EMC CX/AX series hardware.

config DM_MULTIPATH_RDAC
	tristate "LSI/Engenio RDAC multipath support (EXPERIMENTAL)"
	depends on DM_MULTIPATH && BLK_DEV_DM && EXPERIMENTAL
	---help---
	  Multipath support for LSI/Engenio RDAC.

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.

endmenu

endif
Commit	Line	Data
1da177e4 LT	1	#
	2	# Block device driver configuration
	3	#
	4
9361401e DH	5	if BLOCK
9361401e DH	6
1da177e4 LT	7	menu "Multi-device support (RAID and LVM)"
	8
	9	config MD
	10	bool "Multiple devices driver support (RAID and LVM)"
	11	help
	12	Support multiple physical spindles through a single logical device.
	13	Required for RAID and logical volume management.
	14
	15	config BLK_DEV_MD
	16	tristate "RAID support"
	17	depends on MD
	18	---help---
	19	This driver lets you combine several hard disk partitions into one
	20	logical block device. This can be used to simply append one
	21	partition to another one or to combine several redundant hard disks
	22	into a RAID1/4/5 device so as to provide protection against hard
	23	disk failures. This is called "Software RAID" since the combining of
	24	the partitions is done by the kernel. "Hardware RAID" means that the
	25	combining is done by a dedicated controller; if you have such a
	26	controller, you do not need to say Y here.
	27
	28	More information about Software RAID on Linux is contained in the
	29	Software RAID mini-HOWTO, available from
	30	<http://www.tldp.org/docs.html#howto>. There you will also learn
	31	where to get the supporting user space utilities raidtools.
	32
	33	If unsure, say N.
	34
	35	config MD_LINEAR
	36	tristate "Linear (append) mode"
	37	depends on BLK_DEV_MD
	38	---help---
	39	If you say Y here, then your multiple devices driver will be able to
	40	use the so-called linear mode, i.e. it will combine the hard disk
	41	partitions by simply appending one to the other.
	42
	43	To compile this as a module, choose M here: the module
	44	will be called linear.
	45
	46	If unsure, say Y.
	47
	48	config MD_RAID0
	49	tristate "RAID-0 (striping) mode"
	50	depends on BLK_DEV_MD
	51	---help---
	52	If you say Y here, then your multiple devices driver will be able to
	53	use the so-called raid0 mode, i.e. it will combine the hard disk
	54	partitions into one logical device in such a fashion as to fill them
	55	up evenly, one chunk here and one chunk there. This will increase
	56	the throughput rate if the partitions reside on distinct disks.
	57
	58	Information about Software RAID on Linux is contained in the
	59	Software-RAID mini-HOWTO, available from
	60	<http://www.tldp.org/docs.html#howto>. There you will also
	61	learn where to get the supporting user space utilities raidtools.
	62
	63	To compile this as a module, choose M here: the module
	64	will be called raid0.
	65
	66	If unsure, say Y.
	67
	68	config MD_RAID1
	69	tristate "RAID-1 (mirroring) mode"
	70	depends on BLK_DEV_MD
71	---help---
72	A RAID-1 set consists of several disk drives which are exact copies
73	of each other. In the event of a mirror failure, the RAID driver
74	will continue to use the operational mirrors in the set, providing
75	an error free MD (multiple device) to the higher levels of the
76	kernel. In a set with N drives, the available space is the capacity
77	of a single drive, and the set protects against a failure of (N - 1)
78	drives.
79
80	Information about Software RAID on Linux is contained in the
81	Software-RAID mini-HOWTO, available from
82	<http://www.tldp.org/docs.html#howto>. There you will also
83	learn where to get the supporting user space utilities raidtools.
84
85	If you want to use such a RAID-1 set, say Y. To compile this code
86	as a module, choose M here: the module will be called raid1.
87
88	If unsure, say Y.
89
90	config MD_RAID10
91	tristate "RAID-10 (mirrored striping) mode (EXPERIMENTAL)"
92	depends on BLK_DEV_MD && EXPERIMENTAL
93	---help---
94	RAID-10 provides a combination of striping (RAID-0) and
4d2554d0	95	mirroring (RAID-1) with easier configuration and more flexible
1da177e4 LT	96	layout.
	97	Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to
	98	be the same size (or at least, only as much as the smallest device
	99	will be used).
	100	RAID-10 provides a variety of layouts that provide different levels
	101	of redundancy and performance.
	102
	103	RAID-10 requires mdadm-1.7.0 or later, available at:
	104
	105	ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/
	106
	107	If unsure, say Y.
	108
16a53ecc N	109	config MD_RAID456
16a53ecc N	110	tristate "RAID-4/RAID-5/RAID-6 mode"
1da177e4	111	depends on BLK_DEV_MD
9bc89cd8 DW	112	select ASYNC_MEMCPY
9bc89cd8 DW	113	select ASYNC_XOR
1da177e4 LT	114	---help---
	115	A RAID-5 set of N drives with a capacity of C MB per drive provides
	116	the capacity of C * (N - 1) MB, and protects against a failure
	117	of a single drive. For a given sector (row) number, (N - 1) drives
	118	contain data sectors, and one drive contains the parity protection.
	119	For a RAID-4 set, the parity blocks are present on a single drive,
	120	while a RAID-5 set distributes the parity across the drives in one
	121	of the available parity distribution methods.
	122
16a53ecc N	123	A RAID-6 set of N drives with a capacity of C MB per drive
	124	provides the capacity of C * (N - 2) MB, and protects
	125	against a failure of any two drives. For a given sector
	126	(row) number, (N - 2) drives contain data sectors, and two
	127	drives contains two independent redundancy syndromes. Like
	128	RAID-5, RAID-6 distributes the syndromes across the drives
	129	in one of the available parity distribution methods.
	130
1da177e4 LT	131	Information about Software RAID on Linux is contained in the
	132	Software-RAID mini-HOWTO, available from
	133	<http://www.tldp.org/docs.html#howto>. There you will also
	134	learn where to get the supporting user space utilities raidtools.
	135
16a53ecc	136	If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To
1da177e4	137	compile this code as a module, choose M here: the module
16a53ecc	138	will be called raid456.
1da177e4 LT	139
	140	If unsure, say Y.
	141
29269553	142	config MD_RAID5_RESHAPE
14f50b49 N	143	bool "Support adding drives to a raid-5 array"
	144	depends on MD_RAID456
	145	default y
29269553 N	146	---help---
	147	A RAID-5 set can be expanded by adding extra drives. This
	148	requires "restriping" the array which means (almost) every
	149	block must be written to a different place.
	150
	151	This option allows such restriping to be done while the array
14f50b49	152	is online.
29269553	153
4d2554d0	154	You will need mdadm version 2.4.1 or later to use this
6f91fe88 N	155	feature safely. During the early stage of reshape there is
	156	a critical section where live data is being over-written. A
	157	crash during this time needs extra care for recovery. The
	158	newer mdadm takes a copy of the data in the critical section
	159	and will restore it, if necessary, after a crash.
29269553 N	160
	161	The mdadm usage is e.g.
	162	mdadm --grow /dev/md1 --raid-disks=6
	163	to grow '/dev/md1' to having 6 disks.
	164
	165	Note: The array can only be expanded, not contracted.
	166	There should be enough spares already present to make the new
	167	array workable.
	168
14f50b49 N	169	If unsure, say Y.
14f50b49 N	170
1da177e4 LT	171	config MD_MULTIPATH
	172	tristate "Multipath I/O support"
	173	depends on BLK_DEV_MD
	174	help
	175	Multipath-IO is the ability of certain devices to address the same
	176	physical disk over multiple 'IO paths'. The code ensures that such
	177	paths can be defined and handled at runtime, and ensures that a
	178	transparent failover to the backup path(s) happens if a IO errors
	179	arrives on the primary path.
	180
	181	If unsure, say N.
	182
	183	config MD_FAULTY
	184	tristate "Faulty test module for MD"
	185	depends on BLK_DEV_MD
	186	help
	187	The "faulty" module allows for a block device that occasionally returns
	188	read or write errors. It is useful for testing.
	189
	190	In unsure, say N.
	191
	192	config BLK_DEV_DM
	193	tristate "Device mapper support"
	194	depends on MD
	195	---help---
	196	Device-mapper is a low level volume manager. It works by allowing
	197	people to specify mappings for ranges of logical sectors. Various
	198	mapping types are available, in addition people may write their own
	199	modules containing custom mappings if they wish.
	200
	201	Higher level volume managers such as LVM2 use this driver.
	202
	203	To compile this as a module, choose M here: the module will be
	204	called dm-mod.
	205
	206	If unsure, say N.
	207
cc109201 BR	208	config DM_DEBUG
	209	boolean "Device mapper debugging support"
	210	depends on BLK_DEV_DM && EXPERIMENTAL
	211	---help---
	212	Enable this for messages that may help debug device-mapper problems.
	213
	214	If unsure, say N.
	215
1da177e4 LT	216	config DM_CRYPT
	217	tristate "Crypt target support"
	218	depends on BLK_DEV_DM && EXPERIMENTAL
	219	select CRYPTO
3263263f	220	select CRYPTO_CBC
1da177e4 LT	221	---help---
	222	This device-mapper target allows you to create a device that
	223	transparently encrypts the data on it. You'll need to activate
	224	the ciphers you're going to use in the cryptoapi configuration.
	225
	226	Information on how to use dm-crypt can be found on
	227
	228	<http://www.saout.de/misc/dm-crypt/>
	229
	230	To compile this code as a module, choose M here: the module will
	231	be called dm-crypt.
	232
	233	If unsure, say N.
	234
	235	config DM_SNAPSHOT
	236	tristate "Snapshot target (EXPERIMENTAL)"
	237	depends on BLK_DEV_DM && EXPERIMENTAL
	238	---help---
4d2554d0	239	Allow volume managers to take writable snapshots of a device.
1da177e4 LT	240
	241	config DM_MIRROR
	242	tristate "Mirror target (EXPERIMENTAL)"
	243	depends on BLK_DEV_DM && EXPERIMENTAL
	244	---help---
	245	Allow volume managers to mirror logical volumes, also
	246	needed for live data migration tools such as 'pvmove'.
	247
	248	config DM_ZERO
	249	tristate "Zero target (EXPERIMENTAL)"
	250	depends on BLK_DEV_DM && EXPERIMENTAL
	251	---help---
	252	A target that discards writes, and returns all zeroes for
	253	reads. Useful in some recovery situations.
	254
	255	config DM_MULTIPATH
	256	tristate "Multipath target (EXPERIMENTAL)"
	257	depends on BLK_DEV_DM && EXPERIMENTAL
	258	---help---
	259	Allow volume managers to support multipath hardware.
	260
	261	config DM_MULTIPATH_EMC
	262	tristate "EMC CX/AX multipath support (EXPERIMENTAL)"
	263	depends on DM_MULTIPATH && BLK_DEV_DM && EXPERIMENTAL
	264	---help---
	265	Multipath support for EMC CX/AX series hardware.
	266
dd172d72 CS	267	config DM_MULTIPATH_RDAC
	268	tristate "LSI/Engenio RDAC multipath support (EXPERIMENTAL)"
	269	depends on DM_MULTIPATH && BLK_DEV_DM && EXPERIMENTAL
	270	---help---
	271	Multipath support for LSI/Engenio RDAC.
	272
26b9f228 HM	273	config DM_DELAY
	274	tristate "I/O delaying target (EXPERIMENTAL)"
	275	depends on BLK_DEV_DM && EXPERIMENTAL
	276	---help---
	277	A target that delays reads and/or writes and can send
	278	them to different devices. Useful for testing.
	279
	280	If unsure, say N.
	281
1da177e4 LT	282	endmenu
1da177e4 LT	283
9361401e	284	endif