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.
189 tristate "Device mapper support"
191 Device-mapper is a low level volume manager. It works by allowing
192 people to specify mappings for ranges of logical sectors. Various
193 mapping types are available, in addition people may write their own
194 modules containing custom mappings if they wish.
196 Higher level volume managers such as LVM2 use this driver.
198 To compile this as a module, choose M here: the module will be
204 boolean "Device mapper debugging support"
205 depends on BLK_DEV_DM
207 Enable this for messages that may help debug device-mapper problems.
213 depends on BLK_DEV_DM
215 This interface allows you to do buffered I/O on a device and acts
216 as a cache, holding recently-read blocks in memory and performing
221 depends on BLK_DEV_DM
223 Some bio locking schemes used by other device-mapper targets
224 including thin provisioning.
226 source "drivers/md/persistent-data/Kconfig"
229 tristate "Crypt target support"
230 depends on BLK_DEV_DM
234 This device-mapper target allows you to create a device that
235 transparently encrypts the data on it. You'll need to activate
236 the ciphers you're going to use in the cryptoapi configuration.
238 Information on how to use dm-crypt can be found on
240 <http://www.saout.de/misc/dm-crypt/>
242 To compile this code as a module, choose M here: the module will
248 tristate "Snapshot target"
249 depends on BLK_DEV_DM
251 Allow volume managers to take writable snapshots of a device.
253 config DM_THIN_PROVISIONING
254 tristate "Thin provisioning target"
255 depends on BLK_DEV_DM
256 select DM_PERSISTENT_DATA
259 Provides thin provisioning and snapshots that share a data store.
261 config DM_DEBUG_BLOCK_STACK_TRACING
262 boolean "Keep stack trace of thin provisioning block lock holders"
263 depends on STACKTRACE_SUPPORT && DM_THIN_PROVISIONING
266 Enable this for messages that may help debug problems with the
267 block manager locking used by thin provisioning.
272 tristate "Cache target (EXPERIMENTAL)"
273 depends on BLK_DEV_DM
275 select DM_PERSISTENT_DATA
278 dm-cache attempts to improve performance of a block device by
279 moving frequently used data to a smaller, higher performance
280 device. Different 'policy' plugins can be used to change the
281 algorithms used to select which blocks are promoted, demoted,
282 cleaned etc. It supports writeback and writethrough modes.
285 tristate "MQ Cache Policy (EXPERIMENTAL)"
289 A cache policy that uses a multiqueue ordered by recent hit
290 count to select which blocks should be promoted and demoted.
291 This is meant to be a general purpose policy. It prioritises
295 tristate "Mirror target"
296 depends on BLK_DEV_DM
298 Allow volume managers to mirror logical volumes, also
299 needed for live data migration tools such as 'pvmove'.
302 tristate "RAID 1/4/5/6/10 target"
303 depends on BLK_DEV_DM
309 A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings
311 A RAID-5 set of N drives with a capacity of C MB per drive provides
312 the capacity of C * (N - 1) MB, and protects against a failure
313 of a single drive. For a given sector (row) number, (N - 1) drives
314 contain data sectors, and one drive contains the parity protection.
315 For a RAID-4 set, the parity blocks are present on a single drive,
316 while a RAID-5 set distributes the parity across the drives in one
317 of the available parity distribution methods.
319 A RAID-6 set of N drives with a capacity of C MB per drive
320 provides the capacity of C * (N - 2) MB, and protects
321 against a failure of any two drives. For a given sector
322 (row) number, (N - 2) drives contain data sectors, and two
323 drives contains two independent redundancy syndromes. Like
324 RAID-5, RAID-6 distributes the syndromes across the drives
325 in one of the available parity distribution methods.
327 config DM_LOG_USERSPACE
328 tristate "Mirror userspace logging"
329 depends on DM_MIRROR && NET
332 The userspace logging module provides a mechanism for
333 relaying the dm-dirty-log API to userspace. Log designs
334 which are more suited to userspace implementation (e.g.
335 shared storage logs) or experimental logs can be implemented
336 by leveraging this framework.
339 tristate "Zero target"
340 depends on BLK_DEV_DM
342 A target that discards writes, and returns all zeroes for
343 reads. Useful in some recovery situations.
346 tristate "Multipath target"
347 depends on BLK_DEV_DM
348 # nasty syntax but means make DM_MULTIPATH independent
349 # of SCSI_DH if the latter isn't defined but if
350 # it is, DM_MULTIPATH must depend on it. We get a build
351 # error if SCSI_DH=m and DM_MULTIPATH=y
352 depends on SCSI_DH || !SCSI_DH
354 Allow volume managers to support multipath hardware.
356 config DM_MULTIPATH_QL
357 tristate "I/O Path Selector based on the number of in-flight I/Os"
358 depends on DM_MULTIPATH
360 This path selector is a dynamic load balancer which selects
361 the path with the least number of in-flight I/Os.
365 config DM_MULTIPATH_ST
366 tristate "I/O Path Selector based on the service time"
367 depends on DM_MULTIPATH
369 This path selector is a dynamic load balancer which selects
370 the path expected to complete the incoming I/O in the shortest
376 tristate "I/O delaying target"
377 depends on BLK_DEV_DM
379 A target that delays reads and/or writes and can send
380 them to different devices. Useful for testing.
386 depends on BLK_DEV_DM
388 Generate udev events for DM events.
391 tristate "Flakey target"
392 depends on BLK_DEV_DM
394 A target that intermittently fails I/O for debugging purposes.
397 tristate "Verity target support"
398 depends on BLK_DEV_DM
403 This device-mapper target creates a read-only device that
404 transparently validates the data on one underlying device against
405 a pre-generated tree of cryptographic checksums stored on a second
408 You'll need to activate the digests you're going to use in the
409 cryptoapi configuration.
411 To compile this code as a module, choose M here: the module will