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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#
2# Block device driver configuration
3#
4
David Howells93614012006-09-30 20:45:40 +02005if BLOCK
6
Linus Torvalds1da177e2005-04-16 15:20:36 -07007menu "Multi-device support (RAID and LVM)"
8
9config 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
15config 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
35config 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
48config 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
68config 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
90config 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
Justin Piszcz4d2554d2006-06-26 00:27:50 -070095 mirroring (RAID-1) with easier configuration and more flexible
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 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
NeilBrown16a53ec2006-06-26 00:27:38 -0700109config MD_RAID456
110 tristate "RAID-4/RAID-5/RAID-6 mode"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 depends on BLK_DEV_MD
112 ---help---
113 A RAID-5 set of N drives with a capacity of C MB per drive provides
114 the capacity of C * (N - 1) MB, and protects against a failure
115 of a single drive. For a given sector (row) number, (N - 1) drives
116 contain data sectors, and one drive contains the parity protection.
117 For a RAID-4 set, the parity blocks are present on a single drive,
118 while a RAID-5 set distributes the parity across the drives in one
119 of the available parity distribution methods.
120
NeilBrown16a53ec2006-06-26 00:27:38 -0700121 A RAID-6 set of N drives with a capacity of C MB per drive
122 provides the capacity of C * (N - 2) MB, and protects
123 against a failure of any two drives. For a given sector
124 (row) number, (N - 2) drives contain data sectors, and two
125 drives contains two independent redundancy syndromes. Like
126 RAID-5, RAID-6 distributes the syndromes across the drives
127 in one of the available parity distribution methods.
128
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 Information about Software RAID on Linux is contained in the
130 Software-RAID mini-HOWTO, available from
131 <http://www.tldp.org/docs.html#howto>. There you will also
132 learn where to get the supporting user space utilities raidtools.
133
NeilBrown16a53ec2006-06-26 00:27:38 -0700134 If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 compile this code as a module, choose M here: the module
NeilBrown16a53ec2006-06-26 00:27:38 -0700136 will be called raid456.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137
138 If unsure, say Y.
139
NeilBrown29269552006-03-27 01:18:10 -0800140config MD_RAID5_RESHAPE
NeilBrown14f50b42006-10-03 01:16:00 -0700141 bool "Support adding drives to a raid-5 array"
142 depends on MD_RAID456
143 default y
NeilBrown29269552006-03-27 01:18:10 -0800144 ---help---
145 A RAID-5 set can be expanded by adding extra drives. This
146 requires "restriping" the array which means (almost) every
147 block must be written to a different place.
148
149 This option allows such restriping to be done while the array
NeilBrown14f50b42006-10-03 01:16:00 -0700150 is online.
NeilBrown29269552006-03-27 01:18:10 -0800151
Justin Piszcz4d2554d2006-06-26 00:27:50 -0700152 You will need mdadm version 2.4.1 or later to use this
NeilBrown6f91fe82006-04-10 22:52:48 -0700153 feature safely. During the early stage of reshape there is
154 a critical section where live data is being over-written. A
155 crash during this time needs extra care for recovery. The
156 newer mdadm takes a copy of the data in the critical section
157 and will restore it, if necessary, after a crash.
NeilBrown29269552006-03-27 01:18:10 -0800158
159 The mdadm usage is e.g.
160 mdadm --grow /dev/md1 --raid-disks=6
161 to grow '/dev/md1' to having 6 disks.
162
163 Note: The array can only be expanded, not contracted.
164 There should be enough spares already present to make the new
165 array workable.
166
NeilBrown14f50b42006-10-03 01:16:00 -0700167 If unsure, say Y.
168
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169config MD_MULTIPATH
170 tristate "Multipath I/O support"
171 depends on BLK_DEV_MD
172 help
173 Multipath-IO is the ability of certain devices to address the same
174 physical disk over multiple 'IO paths'. The code ensures that such
175 paths can be defined and handled at runtime, and ensures that a
176 transparent failover to the backup path(s) happens if a IO errors
177 arrives on the primary path.
178
179 If unsure, say N.
180
181config MD_FAULTY
182 tristate "Faulty test module for MD"
183 depends on BLK_DEV_MD
184 help
185 The "faulty" module allows for a block device that occasionally returns
186 read or write errors. It is useful for testing.
187
188 In unsure, say N.
189
190config BLK_DEV_DM
191 tristate "Device mapper support"
192 depends on MD
193 ---help---
194 Device-mapper is a low level volume manager. It works by allowing
195 people to specify mappings for ranges of logical sectors. Various
196 mapping types are available, in addition people may write their own
197 modules containing custom mappings if they wish.
198
199 Higher level volume managers such as LVM2 use this driver.
200
201 To compile this as a module, choose M here: the module will be
202 called dm-mod.
203
204 If unsure, say N.
205
Bryn Reevescc109202006-10-03 01:15:35 -0700206config DM_DEBUG
207 boolean "Device mapper debugging support"
208 depends on BLK_DEV_DM && EXPERIMENTAL
209 ---help---
210 Enable this for messages that may help debug device-mapper problems.
211
212 If unsure, say N.
213
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214config DM_CRYPT
215 tristate "Crypt target support"
216 depends on BLK_DEV_DM && EXPERIMENTAL
217 select CRYPTO
Herbert Xu32632632006-12-10 09:50:36 +1100218 select CRYPTO_CBC
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 ---help---
220 This device-mapper target allows you to create a device that
221 transparently encrypts the data on it. You'll need to activate
222 the ciphers you're going to use in the cryptoapi configuration.
223
224 Information on how to use dm-crypt can be found on
225
226 <http://www.saout.de/misc/dm-crypt/>
227
228 To compile this code as a module, choose M here: the module will
229 be called dm-crypt.
230
231 If unsure, say N.
232
233config DM_SNAPSHOT
234 tristate "Snapshot target (EXPERIMENTAL)"
235 depends on BLK_DEV_DM && EXPERIMENTAL
236 ---help---
Justin Piszcz4d2554d2006-06-26 00:27:50 -0700237 Allow volume managers to take writable snapshots of a device.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238
239config DM_MIRROR
240 tristate "Mirror target (EXPERIMENTAL)"
241 depends on BLK_DEV_DM && EXPERIMENTAL
242 ---help---
243 Allow volume managers to mirror logical volumes, also
244 needed for live data migration tools such as 'pvmove'.
245
246config DM_ZERO
247 tristate "Zero target (EXPERIMENTAL)"
248 depends on BLK_DEV_DM && EXPERIMENTAL
249 ---help---
250 A target that discards writes, and returns all zeroes for
251 reads. Useful in some recovery situations.
252
253config DM_MULTIPATH
254 tristate "Multipath target (EXPERIMENTAL)"
255 depends on BLK_DEV_DM && EXPERIMENTAL
256 ---help---
257 Allow volume managers to support multipath hardware.
258
259config DM_MULTIPATH_EMC
260 tristate "EMC CX/AX multipath support (EXPERIMENTAL)"
261 depends on DM_MULTIPATH && BLK_DEV_DM && EXPERIMENTAL
262 ---help---
263 Multipath support for EMC CX/AX series hardware.
264
265endmenu
266
David Howells93614012006-09-30 20:45:40 +0200267endif