2 # Block device driver configuration
6 bool "Multiple devices driver support (RAID and LVM)"
10 Support multiple physical spindles through a single logical device.
11 Required for RAID and logical volume management.
16 tristate "RAID support"
18 This driver lets you combine several hard disk partitions into one
19 logical block device. This can be used to simply append one
20 partition to another one or to combine several redundant hard disks
21 into a RAID1/4/5 device so as to provide protection against hard
22 disk failures. This is called "Software RAID" since the combining of
23 the partitions is done by the kernel. "Hardware RAID" means that the
24 combining is done by a dedicated controller; if you have such a
25 controller, you do not need to say Y here.
27 More information about Software RAID on Linux is contained in the
28 Software RAID mini-HOWTO, available from
29 <http://www.tldp.org/docs.html#howto>. There you will also learn
30 where to get the supporting user space utilities raidtools.
35 bool "Autodetect RAID arrays during kernel boot"
36 depends on BLK_DEV_MD=y
39 If you say Y here, then the kernel will try to autodetect raid
40 arrays as part of its boot process.
42 If you don't use raid and say Y, this autodetection can cause
43 a several-second delay in the boot time due to various
44 synchronisation steps that are part of this step.
49 tristate "Linear (append) mode"
52 If you say Y here, then your multiple devices driver will be able to
53 use the so-called linear mode, i.e. it will combine the hard disk
54 partitions by simply appending one to the other.
56 To compile this as a module, choose M here: the module
57 will be called linear.
62 tristate "RAID-0 (striping) mode"
65 If you say Y here, then your multiple devices driver will be able to
66 use the so-called raid0 mode, i.e. it will combine the hard disk
67 partitions into one logical device in such a fashion as to fill them
68 up evenly, one chunk here and one chunk there. This will increase
69 the throughput rate if the partitions reside on distinct disks.
71 Information about Software RAID on Linux is contained in the
72 Software-RAID mini-HOWTO, available from
73 <http://www.tldp.org/docs.html#howto>. There you will also
74 learn where to get the supporting user space utilities raidtools.
76 To compile this as a module, choose M here: the module
82 tristate "RAID-1 (mirroring) mode"
85 A RAID-1 set consists of several disk drives which are exact copies
86 of each other. In the event of a mirror failure, the RAID driver
87 will continue to use the operational mirrors in the set, providing
88 an error free MD (multiple device) to the higher levels of the
89 kernel. In a set with N drives, the available space is the capacity
90 of a single drive, and the set protects against a failure of (N - 1)
93 Information about Software RAID on Linux is contained in the
94 Software-RAID mini-HOWTO, available from
95 <http://www.tldp.org/docs.html#howto>. There you will also
96 learn where to get the supporting user space utilities raidtools.
98 If you want to use such a RAID-1 set, say Y. To compile this code
99 as a module, choose M here: the module will be called raid1.
104 tristate "RAID-10 (mirrored striping) mode"
105 depends on BLK_DEV_MD
107 RAID-10 provides a combination of striping (RAID-0) and
108 mirroring (RAID-1) with easier configuration and more flexible
110 Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to
111 be the same size (or at least, only as much as the smallest device
113 RAID-10 provides a variety of layouts that provide different levels
114 of redundancy and performance.
116 RAID-10 requires mdadm-1.7.0 or later, available at:
118 ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/
123 tristate "RAID-4/RAID-5/RAID-6 mode"
124 depends on BLK_DEV_MD
130 select ASYNC_RAID6_RECOV
132 A RAID-5 set of N drives with a capacity of C MB per drive provides
133 the capacity of C * (N - 1) MB, and protects against a failure
134 of a single drive. For a given sector (row) number, (N - 1) drives
135 contain data sectors, and one drive contains the parity protection.
136 For a RAID-4 set, the parity blocks are present on a single drive,
137 while a RAID-5 set distributes the parity across the drives in one
138 of the available parity distribution methods.
140 A RAID-6 set of N drives with a capacity of C MB per drive
141 provides the capacity of C * (N - 2) MB, and protects
142 against a failure of any two drives. For a given sector
143 (row) number, (N - 2) drives contain data sectors, and two
144 drives contains two independent redundancy syndromes. Like
145 RAID-5, RAID-6 distributes the syndromes across the drives
146 in one of the available parity distribution methods.
148 Information about Software RAID on Linux is contained in the
149 Software-RAID mini-HOWTO, available from
150 <http://www.tldp.org/docs.html#howto>. There you will also
151 learn where to get the supporting user space utilities raidtools.
153 If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To
154 compile this code as a module, choose M here: the module
155 will be called raid456.
160 tristate "Multipath I/O support"
161 depends on BLK_DEV_MD
163 MD_MULTIPATH provides a simple multi-path personality for use
164 the MD framework. It is not under active development. New
165 projects should consider using DM_MULTIPATH which has more
166 features and more testing.
171 tristate "Faulty test module for MD"
172 depends on BLK_DEV_MD
174 The "faulty" module allows for a block device that occasionally returns
175 read or write errors. It is useful for testing.
181 tristate "Cluster Support for MD (EXPERIMENTAL)"
182 depends on BLK_DEV_MD
186 Clustering support for MD devices. This enables locking and
187 synchronization across multiple systems on the cluster, so all
188 nodes in the cluster can access the MD devices simultaneously.
190 This brings the redundancy (and uptime) of RAID levels across the
191 nodes of the cluster.
195 source "drivers/md/bcache/Kconfig"
197 config BLK_DEV_DM_BUILTIN
201 tristate "Device mapper support"
202 select BLK_DEV_DM_BUILTIN
204 Device-mapper is a low level volume manager. It works by allowing
205 people to specify mappings for ranges of logical sectors. Various
206 mapping types are available, in addition people may write their own
207 modules containing custom mappings if they wish.
209 Higher level volume managers such as LVM2 use this driver.
211 To compile this as a module, choose M here: the module will be
217 bool "request-based DM: use blk-mq I/O path by default"
218 depends on BLK_DEV_DM
220 This option enables the blk-mq based I/O path for request-based
221 DM devices by default. With the option the dm_mod.use_blk_mq
222 module/boot option defaults to Y, without it to N, but it can
223 still be overriden either way.
228 bool "Device mapper debugging support"
229 depends on BLK_DEV_DM
231 Enable this for messages that may help debug device-mapper problems.
237 depends on BLK_DEV_DM
239 This interface allows you to do buffered I/O on a device and acts
240 as a cache, holding recently-read blocks in memory and performing
243 config DM_DEBUG_BLOCK_STACK_TRACING
244 bool "Keep stack trace of persistent data block lock holders"
245 depends on STACKTRACE_SUPPORT && DM_BUFIO
248 Enable this for messages that may help debug problems with the
249 block manager locking used by thin provisioning and caching.
254 depends on BLK_DEV_DM
256 Some bio locking schemes used by other device-mapper targets
257 including thin provisioning.
259 source "drivers/md/persistent-data/Kconfig"
262 tristate "Crypt target support"
263 depends on BLK_DEV_DM
267 This device-mapper target allows you to create a device that
268 transparently encrypts the data on it. You'll need to activate
269 the ciphers you're going to use in the cryptoapi configuration.
271 For further information on dm-crypt and userspace tools see:
272 <https://gitlab.com/cryptsetup/cryptsetup/wikis/DMCrypt>
274 To compile this code as a module, choose M here: the module will
280 tristate "Snapshot target"
281 depends on BLK_DEV_DM
284 Allow volume managers to take writable snapshots of a device.
286 config DM_THIN_PROVISIONING
287 tristate "Thin provisioning target"
288 depends on BLK_DEV_DM
289 select DM_PERSISTENT_DATA
292 Provides thin provisioning and snapshots that share a data store.
295 tristate "Cache target (EXPERIMENTAL)"
296 depends on BLK_DEV_DM
298 select DM_PERSISTENT_DATA
301 dm-cache attempts to improve performance of a block device by
302 moving frequently used data to a smaller, higher performance
303 device. Different 'policy' plugins can be used to change the
304 algorithms used to select which blocks are promoted, demoted,
305 cleaned etc. It supports writeback and writethrough modes.
308 tristate "MQ Cache Policy (EXPERIMENTAL)"
312 A cache policy that uses a multiqueue ordered by recent hit
313 count to select which blocks should be promoted and demoted.
314 This is meant to be a general purpose policy. It prioritises
318 tristate "Stochastic MQ Cache Policy (EXPERIMENTAL)"
322 A cache policy that uses a multiqueue ordered by recent hits
323 to select which blocks should be promoted and demoted.
324 This is meant to be a general purpose policy. It prioritises
325 reads over writes. This SMQ policy (vs MQ) offers the promise
326 of less memory utilization, improved performance and increased
327 adaptability in the face of changing workloads.
329 config DM_CACHE_CLEANER
330 tristate "Cleaner Cache Policy (EXPERIMENTAL)"
334 A simple cache policy that writes back all data to the
335 origin. Used when decommissioning a dm-cache.
338 tristate "Era target (EXPERIMENTAL)"
339 depends on BLK_DEV_DM
341 select DM_PERSISTENT_DATA
344 dm-era tracks which parts of a block device are written to
345 over time. Useful for maintaining cache coherency when using
349 tristate "Mirror target"
350 depends on BLK_DEV_DM
352 Allow volume managers to mirror logical volumes, also
353 needed for live data migration tools such as 'pvmove'.
355 config DM_LOG_USERSPACE
356 tristate "Mirror userspace logging"
357 depends on DM_MIRROR && NET
360 The userspace logging module provides a mechanism for
361 relaying the dm-dirty-log API to userspace. Log designs
362 which are more suited to userspace implementation (e.g.
363 shared storage logs) or experimental logs can be implemented
364 by leveraging this framework.
367 tristate "RAID 1/4/5/6/10 target"
368 depends on BLK_DEV_DM
374 A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings
376 A RAID-5 set of N drives with a capacity of C MB per drive provides
377 the capacity of C * (N - 1) MB, and protects against a failure
378 of a single drive. For a given sector (row) number, (N - 1) drives
379 contain data sectors, and one drive contains the parity protection.
380 For a RAID-4 set, the parity blocks are present on a single drive,
381 while a RAID-5 set distributes the parity across the drives in one
382 of the available parity distribution methods.
384 A RAID-6 set of N drives with a capacity of C MB per drive
385 provides the capacity of C * (N - 2) MB, and protects
386 against a failure of any two drives. For a given sector
387 (row) number, (N - 2) drives contain data sectors, and two
388 drives contains two independent redundancy syndromes. Like
389 RAID-5, RAID-6 distributes the syndromes across the drives
390 in one of the available parity distribution methods.
393 tristate "Zero target"
394 depends on BLK_DEV_DM
396 A target that discards writes, and returns all zeroes for
397 reads. Useful in some recovery situations.
400 tristate "Multipath target"
401 depends on BLK_DEV_DM
402 # nasty syntax but means make DM_MULTIPATH independent
403 # of SCSI_DH if the latter isn't defined but if
404 # it is, DM_MULTIPATH must depend on it. We get a build
405 # error if SCSI_DH=m and DM_MULTIPATH=y
406 depends on !SCSI_DH || SCSI
408 Allow volume managers to support multipath hardware.
410 config DM_MULTIPATH_QL
411 tristate "I/O Path Selector based on the number of in-flight I/Os"
412 depends on DM_MULTIPATH
414 This path selector is a dynamic load balancer which selects
415 the path with the least number of in-flight I/Os.
419 config DM_MULTIPATH_ST
420 tristate "I/O Path Selector based on the service time"
421 depends on DM_MULTIPATH
423 This path selector is a dynamic load balancer which selects
424 the path expected to complete the incoming I/O in the shortest
430 tristate "I/O delaying target"
431 depends on BLK_DEV_DM
433 A target that delays reads and/or writes and can send
434 them to different devices. Useful for testing.
440 depends on BLK_DEV_DM
442 Generate udev events for DM events.
445 tristate "Flakey target"
446 depends on BLK_DEV_DM
448 A target that intermittently fails I/O for debugging purposes.
451 tristate "Verity target support"
452 depends on BLK_DEV_DM
457 This device-mapper target creates a read-only device that
458 transparently validates the data on one underlying device against
459 a pre-generated tree of cryptographic checksums stored on a second
462 You'll need to activate the digests you're going to use in the
463 cryptoapi configuration.
465 To compile this code as a module, choose M here: the module will
471 bool "Verity forward error correction support"
474 select REED_SOLOMON_DEC8
476 Add forward error correction support to dm-verity. This option
477 makes it possible to use pre-generated error correction data to
478 recover from corrupted blocks.
483 tristate "Switch target support (EXPERIMENTAL)"
484 depends on BLK_DEV_DM
486 This device-mapper target creates a device that supports an arbitrary
487 mapping of fixed-size regions of I/O across a fixed set of paths.
488 The path used for any specific region can be switched dynamically
489 by sending the target a message.
491 To compile this code as a module, choose M here: the module will
497 tristate "Log writes target support"
498 depends on BLK_DEV_DM
500 This device-mapper target takes two devices, one device to use
501 normally, one to log all write operations done to the first device.
502 This is for use by file system developers wishing to verify that
503 their fs is writing a consistent file system at all times by allowing
504 them to replay the log in a variety of ways and to check the
507 To compile this code as a module, choose M here: the module will
508 be called dm-log-writes.