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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#
2# Block device driver configuration
3#
4
Jan Engelhardtafd44032007-07-17 04:06:11 -07005menuconfig MD
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 bool "Multiple devices driver support (RAID and LVM)"
Jan Engelhardtafd44032007-07-17 04:06:11 -07007 depends on BLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 help
9 Support multiple physical spindles through a single logical device.
10 Required for RAID and logical volume management.
11
Jan Engelhardtafd44032007-07-17 04:06:11 -070012if MD
13
Linus Torvalds1da177e2005-04-16 15:20:36 -070014config BLK_DEV_MD
15 tristate "RAID support"
Linus Torvalds1da177e2005-04-16 15:20:36 -070016 ---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
Arjan van de Vena3640922008-09-21 15:44:32 -070033config MD_AUTODETECT
34 bool "Autodetect RAID arrays during kernel boot"
Alan Jenkinsce52aeb2008-10-10 16:02:53 +010035 depends on BLK_DEV_MD=y
Arjan van de Vena3640922008-09-21 15:44:32 -070036 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070047config 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
60config 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
80config 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
102config 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
Justin Piszcz4d2554d2006-06-26 00:27:50 -0700107 mirroring (RAID-1) with easier configuration and more flexible
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108 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
NeilBrown16a53ec2006-06-26 00:27:38 -0700121config MD_RAID456
122 tristate "RAID-4/RAID-5/RAID-6 mode"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 depends on BLK_DEV_MD
Dan Williams9bc89cd2007-01-02 11:10:44 -0700124 select ASYNC_MEMCPY
125 select ASYNC_XOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 ---help---
127 A RAID-5 set of N drives with a capacity of C MB per drive provides
128 the capacity of C * (N - 1) MB, and protects against a failure
129 of a single drive. For a given sector (row) number, (N - 1) drives
130 contain data sectors, and one drive contains the parity protection.
131 For a RAID-4 set, the parity blocks are present on a single drive,
132 while a RAID-5 set distributes the parity across the drives in one
133 of the available parity distribution methods.
134
NeilBrown16a53ec2006-06-26 00:27:38 -0700135 A RAID-6 set of N drives with a capacity of C MB per drive
136 provides the capacity of C * (N - 2) MB, and protects
137 against a failure of any two drives. For a given sector
138 (row) number, (N - 2) drives contain data sectors, and two
139 drives contains two independent redundancy syndromes. Like
140 RAID-5, RAID-6 distributes the syndromes across the drives
141 in one of the available parity distribution methods.
142
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 Information about Software RAID on Linux is contained in the
144 Software-RAID mini-HOWTO, available from
145 <http://www.tldp.org/docs.html#howto>. There you will also
146 learn where to get the supporting user space utilities raidtools.
147
NeilBrown16a53ec2006-06-26 00:27:38 -0700148 If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 compile this code as a module, choose M here: the module
NeilBrown16a53ec2006-06-26 00:27:38 -0700150 will be called raid456.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151
152 If unsure, say Y.
153
NeilBrown29269552006-03-27 01:18:10 -0800154config MD_RAID5_RESHAPE
NeilBrown14f50b42006-10-03 01:16:00 -0700155 bool "Support adding drives to a raid-5 array"
156 depends on MD_RAID456
157 default y
NeilBrown29269552006-03-27 01:18:10 -0800158 ---help---
159 A RAID-5 set can be expanded by adding extra drives. This
160 requires "restriping" the array which means (almost) every
161 block must be written to a different place.
162
163 This option allows such restriping to be done while the array
NeilBrown14f50b42006-10-03 01:16:00 -0700164 is online.
NeilBrown29269552006-03-27 01:18:10 -0800165
Justin Piszcz4d2554d2006-06-26 00:27:50 -0700166 You will need mdadm version 2.4.1 or later to use this
NeilBrown6f91fe82006-04-10 22:52:48 -0700167 feature safely. During the early stage of reshape there is
168 a critical section where live data is being over-written. A
169 crash during this time needs extra care for recovery. The
170 newer mdadm takes a copy of the data in the critical section
171 and will restore it, if necessary, after a crash.
NeilBrown29269552006-03-27 01:18:10 -0800172
173 The mdadm usage is e.g.
174 mdadm --grow /dev/md1 --raid-disks=6
175 to grow '/dev/md1' to having 6 disks.
176
177 Note: The array can only be expanded, not contracted.
178 There should be enough spares already present to make the new
179 array workable.
180
NeilBrown14f50b42006-10-03 01:16:00 -0700181 If unsure, say Y.
182
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183config MD_MULTIPATH
184 tristate "Multipath I/O support"
185 depends on BLK_DEV_MD
186 help
187 Multipath-IO is the ability of certain devices to address the same
188 physical disk over multiple 'IO paths'. The code ensures that such
189 paths can be defined and handled at runtime, and ensures that a
190 transparent failover to the backup path(s) happens if a IO errors
191 arrives on the primary path.
192
193 If unsure, say N.
194
195config 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
204config BLK_DEV_DM
205 tristate "Device mapper support"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 ---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
Bryn Reevescc109202006-10-03 01:15:35 -0700219config DM_DEBUG
220 boolean "Device mapper debugging support"
Alasdair G Kergon0149e572008-02-08 02:10:32 +0000221 depends on BLK_DEV_DM
Bryn Reevescc109202006-10-03 01:15:35 -0700222 ---help---
223 Enable this for messages that may help debug device-mapper problems.
224
225 If unsure, say N.
226
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227config DM_CRYPT
228 tristate "Crypt target support"
Alasdair G Kergon0149e572008-02-08 02:10:32 +0000229 depends on BLK_DEV_DM
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 select CRYPTO
Herbert Xu32632632006-12-10 09:50:36 +1100231 select CRYPTO_CBC
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 ---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
246config DM_SNAPSHOT
Alasdair G Kergon0149e572008-02-08 02:10:32 +0000247 tristate "Snapshot target"
248 depends on BLK_DEV_DM
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 ---help---
Justin Piszcz4d2554d2006-06-26 00:27:50 -0700250 Allow volume managers to take writable snapshots of a device.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251
252config DM_MIRROR
Alasdair G Kergon0149e572008-02-08 02:10:32 +0000253 tristate "Mirror target"
254 depends on BLK_DEV_DM
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 ---help---
256 Allow volume managers to mirror logical volumes, also
257 needed for live data migration tools such as 'pvmove'.
258
259config DM_ZERO
Alasdair G Kergon0149e572008-02-08 02:10:32 +0000260 tristate "Zero target"
261 depends on BLK_DEV_DM
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 ---help---
263 A target that discards writes, and returns all zeroes for
264 reads. Useful in some recovery situations.
265
266config DM_MULTIPATH
Alasdair G Kergon0149e572008-02-08 02:10:32 +0000267 tristate "Multipath target"
268 depends on BLK_DEV_DM
Chandra Seetharamanfe9233f2008-05-23 18:16:40 -0700269 # nasty syntax but means make DM_MULTIPATH independent
270 # of SCSI_DH if the latter isn't defined but if
271 # it is, DM_MULTIPATH must depend on it. We get a build
272 # error if SCSI_DH=m and DM_MULTIPATH=y
273 depends on SCSI_DH || !SCSI_DH
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 ---help---
275 Allow volume managers to support multipath hardware.
276
Heinz Mauelshagen26b9f222007-05-09 02:33:06 -0700277config DM_DELAY
278 tristate "I/O delaying target (EXPERIMENTAL)"
279 depends on BLK_DEV_DM && EXPERIMENTAL
280 ---help---
281 A target that delays reads and/or writes and can send
282 them to different devices. Useful for testing.
283
284 If unsure, say N.
285
Mike Anderson51e5b2b2007-10-19 22:48:00 +0100286config DM_UEVENT
287 bool "DM uevents (EXPERIMENTAL)"
288 depends on BLK_DEV_DM && EXPERIMENTAL
289 ---help---
290 Generate udev events for DM events.
291
Jan Engelhardtafd44032007-07-17 04:06:11 -0700292endif # MD