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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#
2# Block device driver configuration
3#
4
5menu "Multi-device support (RAID and LVM)"
6
7config MD
8 bool "Multiple devices driver support (RAID and LVM)"
9 help
10 Support multiple physical spindles through a single logical device.
11 Required for RAID and logical volume management.
12
13config BLK_DEV_MD
14 tristate "RAID support"
15 depends on MD
16 ---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
33config MD_LINEAR
34 tristate "Linear (append) mode"
35 depends on BLK_DEV_MD
36 ---help---
37 If you say Y here, then your multiple devices driver will be able to
38 use the so-called linear mode, i.e. it will combine the hard disk
39 partitions by simply appending one to the other.
40
41 To compile this as a module, choose M here: the module
42 will be called linear.
43
44 If unsure, say Y.
45
46config MD_RAID0
47 tristate "RAID-0 (striping) mode"
48 depends on BLK_DEV_MD
49 ---help---
50 If you say Y here, then your multiple devices driver will be able to
51 use the so-called raid0 mode, i.e. it will combine the hard disk
52 partitions into one logical device in such a fashion as to fill them
53 up evenly, one chunk here and one chunk there. This will increase
54 the throughput rate if the partitions reside on distinct disks.
55
56 Information about Software RAID on Linux is contained in the
57 Software-RAID mini-HOWTO, available from
58 <http://www.tldp.org/docs.html#howto>. There you will also
59 learn where to get the supporting user space utilities raidtools.
60
61 To compile this as a module, choose M here: the module
62 will be called raid0.
63
64 If unsure, say Y.
65
66config MD_RAID1
67 tristate "RAID-1 (mirroring) mode"
68 depends on BLK_DEV_MD
69 ---help---
70 A RAID-1 set consists of several disk drives which are exact copies
71 of each other. In the event of a mirror failure, the RAID driver
72 will continue to use the operational mirrors in the set, providing
73 an error free MD (multiple device) to the higher levels of the
74 kernel. In a set with N drives, the available space is the capacity
75 of a single drive, and the set protects against a failure of (N - 1)
76 drives.
77
78 Information about Software RAID on Linux is contained in the
79 Software-RAID mini-HOWTO, available from
80 <http://www.tldp.org/docs.html#howto>. There you will also
81 learn where to get the supporting user space utilities raidtools.
82
83 If you want to use such a RAID-1 set, say Y. To compile this code
84 as a module, choose M here: the module will be called raid1.
85
86 If unsure, say Y.
87
88config MD_RAID10
89 tristate "RAID-10 (mirrored striping) mode (EXPERIMENTAL)"
90 depends on BLK_DEV_MD && EXPERIMENTAL
91 ---help---
92 RAID-10 provides a combination of striping (RAID-0) and
93 mirroring (RAID-1) with easier configuration and more flexable
94 layout.
95 Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to
96 be the same size (or at least, only as much as the smallest device
97 will be used).
98 RAID-10 provides a variety of layouts that provide different levels
99 of redundancy and performance.
100
101 RAID-10 requires mdadm-1.7.0 or later, available at:
102
103 ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/
104
105 If unsure, say Y.
106
NeilBrown16a53ec2006-06-26 00:27:38 -0700107config MD_RAID456
108 tristate "RAID-4/RAID-5/RAID-6 mode"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109 depends on BLK_DEV_MD
110 ---help---
111 A RAID-5 set of N drives with a capacity of C MB per drive provides
112 the capacity of C * (N - 1) MB, and protects against a failure
113 of a single drive. For a given sector (row) number, (N - 1) drives
114 contain data sectors, and one drive contains the parity protection.
115 For a RAID-4 set, the parity blocks are present on a single drive,
116 while a RAID-5 set distributes the parity across the drives in one
117 of the available parity distribution methods.
118
NeilBrown16a53ec2006-06-26 00:27:38 -0700119 A RAID-6 set of N drives with a capacity of C MB per drive
120 provides the capacity of C * (N - 2) MB, and protects
121 against a failure of any two drives. For a given sector
122 (row) number, (N - 2) drives contain data sectors, and two
123 drives contains two independent redundancy syndromes. Like
124 RAID-5, RAID-6 distributes the syndromes across the drives
125 in one of the available parity distribution methods.
126
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 Information about Software RAID on Linux is contained in the
128 Software-RAID mini-HOWTO, available from
129 <http://www.tldp.org/docs.html#howto>. There you will also
130 learn where to get the supporting user space utilities raidtools.
131
NeilBrown16a53ec2006-06-26 00:27:38 -0700132 If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 compile this code as a module, choose M here: the module
NeilBrown16a53ec2006-06-26 00:27:38 -0700134 will be called raid456.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135
136 If unsure, say Y.
137
NeilBrown29269552006-03-27 01:18:10 -0800138config MD_RAID5_RESHAPE
139 bool "Support adding drives to a raid-5 array (experimental)"
140 depends on MD_RAID5 && EXPERIMENTAL
141 ---help---
142 A RAID-5 set can be expanded by adding extra drives. This
143 requires "restriping" the array which means (almost) every
144 block must be written to a different place.
145
146 This option allows such restriping to be done while the array
147 is online. However it is still EXPERIMENTAL code. It should
148 work, but please be sure that you have backups.
149
NeilBrown6f91fe82006-04-10 22:52:48 -0700150 You will need mdadm verion 2.4.1 or later to use this
151 feature safely. During the early stage of reshape there is
152 a critical section where live data is being over-written. A
153 crash during this time needs extra care for recovery. The
154 newer mdadm takes a copy of the data in the critical section
155 and will restore it, if necessary, after a crash.
NeilBrown29269552006-03-27 01:18:10 -0800156
157 The mdadm usage is e.g.
158 mdadm --grow /dev/md1 --raid-disks=6
159 to grow '/dev/md1' to having 6 disks.
160
161 Note: The array can only be expanded, not contracted.
162 There should be enough spares already present to make the new
163 array workable.
164
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165config MD_MULTIPATH
166 tristate "Multipath I/O support"
167 depends on BLK_DEV_MD
168 help
169 Multipath-IO is the ability of certain devices to address the same
170 physical disk over multiple 'IO paths'. The code ensures that such
171 paths can be defined and handled at runtime, and ensures that a
172 transparent failover to the backup path(s) happens if a IO errors
173 arrives on the primary path.
174
175 If unsure, say N.
176
177config MD_FAULTY
178 tristate "Faulty test module for MD"
179 depends on BLK_DEV_MD
180 help
181 The "faulty" module allows for a block device that occasionally returns
182 read or write errors. It is useful for testing.
183
184 In unsure, say N.
185
186config BLK_DEV_DM
187 tristate "Device mapper support"
188 depends on MD
189 ---help---
190 Device-mapper is a low level volume manager. It works by allowing
191 people to specify mappings for ranges of logical sectors. Various
192 mapping types are available, in addition people may write their own
193 modules containing custom mappings if they wish.
194
195 Higher level volume managers such as LVM2 use this driver.
196
197 To compile this as a module, choose M here: the module will be
198 called dm-mod.
199
200 If unsure, say N.
201
202config DM_CRYPT
203 tristate "Crypt target support"
204 depends on BLK_DEV_DM && EXPERIMENTAL
205 select CRYPTO
206 ---help---
207 This device-mapper target allows you to create a device that
208 transparently encrypts the data on it. You'll need to activate
209 the ciphers you're going to use in the cryptoapi configuration.
210
211 Information on how to use dm-crypt can be found on
212
213 <http://www.saout.de/misc/dm-crypt/>
214
215 To compile this code as a module, choose M here: the module will
216 be called dm-crypt.
217
218 If unsure, say N.
219
220config DM_SNAPSHOT
221 tristate "Snapshot target (EXPERIMENTAL)"
222 depends on BLK_DEV_DM && EXPERIMENTAL
223 ---help---
224 Allow volume managers to take writeable snapshots of a device.
225
226config DM_MIRROR
227 tristate "Mirror target (EXPERIMENTAL)"
228 depends on BLK_DEV_DM && EXPERIMENTAL
229 ---help---
230 Allow volume managers to mirror logical volumes, also
231 needed for live data migration tools such as 'pvmove'.
232
233config DM_ZERO
234 tristate "Zero target (EXPERIMENTAL)"
235 depends on BLK_DEV_DM && EXPERIMENTAL
236 ---help---
237 A target that discards writes, and returns all zeroes for
238 reads. Useful in some recovery situations.
239
240config DM_MULTIPATH
241 tristate "Multipath target (EXPERIMENTAL)"
242 depends on BLK_DEV_DM && EXPERIMENTAL
243 ---help---
244 Allow volume managers to support multipath hardware.
245
246config DM_MULTIPATH_EMC
247 tristate "EMC CX/AX multipath support (EXPERIMENTAL)"
248 depends on DM_MULTIPATH && BLK_DEV_DM && EXPERIMENTAL
249 ---help---
250 Multipath support for EMC CX/AX series hardware.
251
252endmenu
253