[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 XOR_BLOCKS
	---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_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
685784aa	112	select XOR_BLOCKS
1da177e4 LT	113	---help---
	114	A RAID-5 set of N drives with a capacity of C MB per drive provides
	115	the capacity of C * (N - 1) MB, and protects against a failure
	116	of a single drive. For a given sector (row) number, (N - 1) drives
	117	contain data sectors, and one drive contains the parity protection.
	118	For a RAID-4 set, the parity blocks are present on a single drive,
	119	while a RAID-5 set distributes the parity across the drives in one
	120	of the available parity distribution methods.
	121
16a53ecc N	122	A RAID-6 set of N drives with a capacity of C MB per drive
	123	provides the capacity of C * (N - 2) MB, and protects
	124	against a failure of any two drives. For a given sector
	125	(row) number, (N - 2) drives contain data sectors, and two
	126	drives contains two independent redundancy syndromes. Like
	127	RAID-5, RAID-6 distributes the syndromes across the drives
	128	in one of the available parity distribution methods.
	129
1da177e4 LT	130	Information about Software RAID on Linux is contained in the
	131	Software-RAID mini-HOWTO, available from
	132	<http://www.tldp.org/docs.html#howto>. There you will also
	133	learn where to get the supporting user space utilities raidtools.
	134
16a53ecc	135	If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To
1da177e4	136	compile this code as a module, choose M here: the module
16a53ecc	137	will be called raid456.
1da177e4 LT	138
	139	If unsure, say Y.
	140
29269553	141	config MD_RAID5_RESHAPE
14f50b49 N	142	bool "Support adding drives to a raid-5 array"
	143	depends on MD_RAID456
	144	default y
29269553 N	145	---help---
	146	A RAID-5 set can be expanded by adding extra drives. This
	147	requires "restriping" the array which means (almost) every
	148	block must be written to a different place.
	149
	150	This option allows such restriping to be done while the array
14f50b49	151	is online.
29269553	152
4d2554d0	153	You will need mdadm version 2.4.1 or later to use this
6f91fe88 N	154	feature safely. During the early stage of reshape there is
	155	a critical section where live data is being over-written. A
	156	crash during this time needs extra care for recovery. The
	157	newer mdadm takes a copy of the data in the critical section
	158	and will restore it, if necessary, after a crash.
29269553 N	159
	160	The mdadm usage is e.g.
	161	mdadm --grow /dev/md1 --raid-disks=6
	162	to grow '/dev/md1' to having 6 disks.
	163
	164	Note: The array can only be expanded, not contracted.
	165	There should be enough spares already present to make the new
	166	array workable.
	167
14f50b49 N	168	If unsure, say Y.
14f50b49 N	169
1da177e4 LT	170	config MD_MULTIPATH
	171	tristate "Multipath I/O support"
	172	depends on BLK_DEV_MD
	173	help
	174	Multipath-IO is the ability of certain devices to address the same
	175	physical disk over multiple 'IO paths'. The code ensures that such
	176	paths can be defined and handled at runtime, and ensures that a
	177	transparent failover to the backup path(s) happens if a IO errors
	178	arrives on the primary path.
	179
	180	If unsure, say N.
	181
	182	config MD_FAULTY
	183	tristate "Faulty test module for MD"
	184	depends on BLK_DEV_MD
	185	help
	186	The "faulty" module allows for a block device that occasionally returns
	187	read or write errors. It is useful for testing.
	188
	189	In unsure, say N.
	190
	191	config BLK_DEV_DM
	192	tristate "Device mapper support"
	193	depends on MD
	194	---help---
	195	Device-mapper is a low level volume manager. It works by allowing
	196	people to specify mappings for ranges of logical sectors. Various
	197	mapping types are available, in addition people may write their own
	198	modules containing custom mappings if they wish.
	199
	200	Higher level volume managers such as LVM2 use this driver.
	201
	202	To compile this as a module, choose M here: the module will be
	203	called dm-mod.
	204
	205	If unsure, say N.
	206
cc109201 BR	207	config DM_DEBUG
	208	boolean "Device mapper debugging support"
	209	depends on BLK_DEV_DM && EXPERIMENTAL
	210	---help---
	211	Enable this for messages that may help debug device-mapper problems.
	212
	213	If unsure, say N.
	214
1da177e4 LT	215	config DM_CRYPT
	216	tristate "Crypt target support"
	217	depends on BLK_DEV_DM && EXPERIMENTAL
	218	select CRYPTO
3263263f	219	select CRYPTO_CBC
1da177e4 LT	220	---help---
	221	This device-mapper target allows you to create a device that
	222	transparently encrypts the data on it. You'll need to activate
	223	the ciphers you're going to use in the cryptoapi configuration.
	224
	225	Information on how to use dm-crypt can be found on
	226
	227	<http://www.saout.de/misc/dm-crypt/>
	228
	229	To compile this code as a module, choose M here: the module will
	230	be called dm-crypt.
	231
	232	If unsure, say N.
	233
	234	config DM_SNAPSHOT
	235	tristate "Snapshot target (EXPERIMENTAL)"
	236	depends on BLK_DEV_DM && EXPERIMENTAL
	237	---help---
4d2554d0	238	Allow volume managers to take writable snapshots of a device.
1da177e4 LT	239
	240	config DM_MIRROR
	241	tristate "Mirror target (EXPERIMENTAL)"
	242	depends on BLK_DEV_DM && EXPERIMENTAL
	243	---help---
	244	Allow volume managers to mirror logical volumes, also
	245	needed for live data migration tools such as 'pvmove'.
	246
	247	config DM_ZERO
	248	tristate "Zero target (EXPERIMENTAL)"
	249	depends on BLK_DEV_DM && EXPERIMENTAL
	250	---help---
	251	A target that discards writes, and returns all zeroes for
	252	reads. Useful in some recovery situations.
	253
	254	config DM_MULTIPATH
	255	tristate "Multipath target (EXPERIMENTAL)"
	256	depends on BLK_DEV_DM && EXPERIMENTAL
	257	---help---
	258	Allow volume managers to support multipath hardware.
	259
	260	config DM_MULTIPATH_EMC
	261	tristate "EMC CX/AX multipath support (EXPERIMENTAL)"
	262	depends on DM_MULTIPATH && BLK_DEV_DM && EXPERIMENTAL
	263	---help---
	264	Multipath support for EMC CX/AX series hardware.
	265
26b9f228 HM	266	config DM_DELAY
	267	tristate "I/O delaying target (EXPERIMENTAL)"
	268	depends on BLK_DEV_DM && EXPERIMENTAL
	269	---help---
	270	A target that delays reads and/or writes and can send
	271	them to different devices. Useful for testing.
	272
	273	If unsure, say N.
	274
1da177e4 LT	275	endmenu
1da177e4 LT	276
9361401e	277	endif