2 # Block device driver configuration
6 bool "Multiple devices driver support (RAID and LVM)"
9 Support multiple physical spindles through a single logical device.
10 Required for RAID and logical volume management.
15 tristate "RAID support"
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.
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.
34 bool "Autodetect RAID arrays during kernel boot"
35 depends on BLK_DEV_MD=y
38 If you say Y here, then the kernel will try to autodetect raid
39 arrays as part of its boot process.
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.
48 tristate "Linear (append) mode"
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.
55 To compile this as a module, choose M here: the module
56 will be called linear.
61 tristate "RAID-0 (striping) mode"
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.
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.
75 To compile this as a module, choose M here: the module
81 tristate "RAID-1 (mirroring) mode"
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)
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.
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.
103 tristate "RAID-10 (mirrored striping) mode"
104 depends on BLK_DEV_MD
106 RAID-10 provides a combination of striping (RAID-0) and
107 mirroring (RAID-1) with easier configuration and more flexible
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
112 RAID-10 provides a variety of layouts that provide different levels
113 of redundancy and performance.
115 RAID-10 requires mdadm-1.7.0 or later, available at:
117 ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/
122 tristate "RAID-4/RAID-5/RAID-6 mode"
123 depends on BLK_DEV_MD
128 select ASYNC_RAID6_RECOV
130 A RAID-5 set of N drives with a capacity of C MB per drive provides
131 the capacity of C * (N - 1) MB, and protects against a failure
132 of a single drive. For a given sector (row) number, (N - 1) drives
133 contain data sectors, and one drive contains the parity protection.
134 For a RAID-4 set, the parity blocks are present on a single drive,
135 while a RAID-5 set distributes the parity across the drives in one
136 of the available parity distribution methods.
138 A RAID-6 set of N drives with a capacity of C MB per drive
139 provides the capacity of C * (N - 2) MB, and protects
140 against a failure of any two drives. For a given sector
141 (row) number, (N - 2) drives contain data sectors, and two
142 drives contains two independent redundancy syndromes. Like
143 RAID-5, RAID-6 distributes the syndromes across the drives
144 in one of the available parity distribution methods.
146 Information about Software RAID on Linux is contained in the
147 Software-RAID mini-HOWTO, available from
148 <http://www.tldp.org/docs.html#howto>. There you will also
149 learn where to get the supporting user space utilities raidtools.
151 If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To
152 compile this code as a module, choose M here: the module
153 will be called raid456.
157 config MULTICORE_RAID456
158 bool "RAID-4/RAID-5/RAID-6 Multicore processing (EXPERIMENTAL)"
159 depends on MD_RAID456
161 depends on EXPERIMENTAL
163 Enable the raid456 module to dispatch per-stripe raid operations to a
169 tristate "Multipath I/O support"
170 depends on BLK_DEV_MD
172 MD_MULTIPATH provides a simple multi-path personality for use
173 the MD framework. It is not under active development. New
174 projects should consider using DM_MULTIPATH which has more
175 features and more testing.
180 tristate "Faulty test module for MD"
181 depends on BLK_DEV_MD
183 The "faulty" module allows for a block device that occasionally returns
184 read or write errors. It is useful for testing.
188 config BLK_DEV_DM_BUILTIN
192 tristate "Device mapper support"
193 select BLK_DEV_DM_BUILTIN
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.
200 Higher level volume managers such as LVM2 use this driver.
202 To compile this as a module, choose M here: the module will be
208 boolean "Device mapper debugging support"
209 depends on BLK_DEV_DM
211 Enable this for messages that may help debug device-mapper problems.
217 depends on BLK_DEV_DM && EXPERIMENTAL
219 This interface allows you to do buffered I/O on a device and acts
220 as a cache, holding recently-read blocks in memory and performing
223 source "drivers/md/persistent-data/Kconfig"
226 tristate "Crypt target support"
227 depends on BLK_DEV_DM
231 This device-mapper target allows you to create a device that
232 transparently encrypts the data on it. You'll need to activate
233 the ciphers you're going to use in the cryptoapi configuration.
235 Information on how to use dm-crypt can be found on
237 <http://www.saout.de/misc/dm-crypt/>
239 To compile this code as a module, choose M here: the module will
245 tristate "Snapshot target"
246 depends on BLK_DEV_DM
248 Allow volume managers to take writable snapshots of a device.
250 config DM_THIN_PROVISIONING
251 tristate "Thin provisioning target (EXPERIMENTAL)"
252 depends on BLK_DEV_DM && EXPERIMENTAL
253 select DM_PERSISTENT_DATA
255 Provides thin provisioning and snapshots that share a data store.
257 config DM_DEBUG_BLOCK_STACK_TRACING
258 boolean "Keep stack trace of thin provisioning block lock holders"
259 depends on STACKTRACE_SUPPORT && DM_THIN_PROVISIONING
262 Enable this for messages that may help debug problems with the
263 block manager locking used by thin provisioning.
267 config DM_DEBUG_SPACE_MAPS
268 boolean "Extra validation for thin provisioning space maps"
269 depends on DM_THIN_PROVISIONING
271 Enable this for messages that may help debug problems with the
272 space maps used by thin provisioning.
277 tristate "Mirror target"
278 depends on BLK_DEV_DM
280 Allow volume managers to mirror logical volumes, also
281 needed for live data migration tools such as 'pvmove'.
284 tristate "RAID 1/4/5/6 target (EXPERIMENTAL)"
285 depends on BLK_DEV_DM && EXPERIMENTAL
290 A dm target that supports RAID1, RAID4, RAID5 and RAID6 mappings
292 A RAID-5 set of N drives with a capacity of C MB per drive provides
293 the capacity of C * (N - 1) MB, and protects against a failure
294 of a single drive. For a given sector (row) number, (N - 1) drives
295 contain data sectors, and one drive contains the parity protection.
296 For a RAID-4 set, the parity blocks are present on a single drive,
297 while a RAID-5 set distributes the parity across the drives in one
298 of the available parity distribution methods.
300 A RAID-6 set of N drives with a capacity of C MB per drive
301 provides the capacity of C * (N - 2) MB, and protects
302 against a failure of any two drives. For a given sector
303 (row) number, (N - 2) drives contain data sectors, and two
304 drives contains two independent redundancy syndromes. Like
305 RAID-5, RAID-6 distributes the syndromes across the drives
306 in one of the available parity distribution methods.
308 config DM_LOG_USERSPACE
309 tristate "Mirror userspace logging (EXPERIMENTAL)"
310 depends on DM_MIRROR && EXPERIMENTAL && NET
313 The userspace logging module provides a mechanism for
314 relaying the dm-dirty-log API to userspace. Log designs
315 which are more suited to userspace implementation (e.g.
316 shared storage logs) or experimental logs can be implemented
317 by leveraging this framework.
320 tristate "Zero target"
321 depends on BLK_DEV_DM
323 A target that discards writes, and returns all zeroes for
324 reads. Useful in some recovery situations.
327 tristate "Multipath target"
328 depends on BLK_DEV_DM
329 # nasty syntax but means make DM_MULTIPATH independent
330 # of SCSI_DH if the latter isn't defined but if
331 # it is, DM_MULTIPATH must depend on it. We get a build
332 # error if SCSI_DH=m and DM_MULTIPATH=y
333 depends on SCSI_DH || !SCSI_DH
335 Allow volume managers to support multipath hardware.
337 config DM_MULTIPATH_QL
338 tristate "I/O Path Selector based on the number of in-flight I/Os"
339 depends on DM_MULTIPATH
341 This path selector is a dynamic load balancer which selects
342 the path with the least number of in-flight I/Os.
346 config DM_MULTIPATH_ST
347 tristate "I/O Path Selector based on the service time"
348 depends on DM_MULTIPATH
350 This path selector is a dynamic load balancer which selects
351 the path expected to complete the incoming I/O in the shortest
357 tristate "I/O delaying target (EXPERIMENTAL)"
358 depends on BLK_DEV_DM && EXPERIMENTAL
360 A target that delays reads and/or writes and can send
361 them to different devices. Useful for testing.
366 bool "DM uevents (EXPERIMENTAL)"
367 depends on BLK_DEV_DM && EXPERIMENTAL
369 Generate udev events for DM events.
372 tristate "Flakey target (EXPERIMENTAL)"
373 depends on BLK_DEV_DM && EXPERIMENTAL
375 A target that intermittently fails I/O for debugging purposes.