1 # SPDX-License-Identifier: GPL-2.0-only
3 # Block device driver configuration
7 bool "Multiple devices driver support (RAID and LVM)"
11 Support multiple physical spindles through a single logical device.
12 Required for RAID and logical volume management.
17 tristate "RAID support"
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.
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.
36 bool "Autodetect RAID arrays during kernel boot"
37 depends on BLK_DEV_MD=y
40 If you say Y here, then the kernel will try to autodetect raid
41 arrays as part of its boot process.
43 If you don't use raid and say Y, this autodetection can cause
44 a several-second delay in the boot time due to various
45 synchronisation steps that are part of this step.
50 tristate "Linear (append) mode"
53 If you say Y here, then your multiple devices driver will be able to
54 use the so-called linear mode, i.e. it will combine the hard disk
55 partitions by simply appending one to the other.
57 To compile this as a module, choose M here: the module
58 will be called linear.
63 tristate "RAID-0 (striping) mode"
66 If you say Y here, then your multiple devices driver will be able to
67 use the so-called raid0 mode, i.e. it will combine the hard disk
68 partitions into one logical device in such a fashion as to fill them
69 up evenly, one chunk here and one chunk there. This will increase
70 the throughput rate if the partitions reside on distinct disks.
72 Information about Software RAID on Linux is contained in the
73 Software-RAID mini-HOWTO, available from
74 <http://www.tldp.org/docs.html#howto>. There you will also
75 learn where to get the supporting user space utilities raidtools.
77 To compile this as a module, choose M here: the module
83 tristate "RAID-1 (mirroring) mode"
86 A RAID-1 set consists of several disk drives which are exact copies
87 of each other. In the event of a mirror failure, the RAID driver
88 will continue to use the operational mirrors in the set, providing
89 an error free MD (multiple device) to the higher levels of the
90 kernel. In a set with N drives, the available space is the capacity
91 of a single drive, and the set protects against a failure of (N - 1)
94 Information about Software RAID on Linux is contained in the
95 Software-RAID mini-HOWTO, available from
96 <http://www.tldp.org/docs.html#howto>. There you will also
97 learn where to get the supporting user space utilities raidtools.
99 If you want to use such a RAID-1 set, say Y. To compile this code
100 as a module, choose M here: the module will be called raid1.
105 tristate "RAID-10 (mirrored striping) mode"
106 depends on BLK_DEV_MD
108 RAID-10 provides a combination of striping (RAID-0) and
109 mirroring (RAID-1) with easier configuration and more flexible
111 Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to
112 be the same size (or at least, only as much as the smallest device
114 RAID-10 provides a variety of layouts that provide different levels
115 of redundancy and performance.
117 RAID-10 requires mdadm-1.7.0 or later, available at:
119 https://www.kernel.org/pub/linux/utils/raid/mdadm/
124 tristate "RAID-4/RAID-5/RAID-6 mode"
125 depends on BLK_DEV_MD
131 select ASYNC_RAID6_RECOV
133 A RAID-5 set of N drives with a capacity of C MB per drive provides
134 the capacity of C * (N - 1) MB, and protects against a failure
135 of a single drive. For a given sector (row) number, (N - 1) drives
136 contain data sectors, and one drive contains the parity protection.
137 For a RAID-4 set, the parity blocks are present on a single drive,
138 while a RAID-5 set distributes the parity across the drives in one
139 of the available parity distribution methods.
141 A RAID-6 set of N drives with a capacity of C MB per drive
142 provides the capacity of C * (N - 2) MB, and protects
143 against a failure of any two drives. For a given sector
144 (row) number, (N - 2) drives contain data sectors, and two
145 drives contains two independent redundancy syndromes. Like
146 RAID-5, RAID-6 distributes the syndromes across the drives
147 in one of the available parity distribution methods.
149 Information about Software RAID on Linux is contained in the
150 Software-RAID mini-HOWTO, available from
151 <http://www.tldp.org/docs.html#howto>. There you will also
152 learn where to get the supporting user space utilities raidtools.
154 If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To
155 compile this code as a module, choose M here: the module
156 will be called raid456.
161 tristate "Multipath I/O support"
162 depends on BLK_DEV_MD
164 MD_MULTIPATH provides a simple multi-path personality for use
165 the MD framework. It is not under active development. New
166 projects should consider using DM_MULTIPATH which has more
167 features and more testing.
172 tristate "Faulty test module for MD"
173 depends on BLK_DEV_MD
175 The "faulty" module allows for a block device that occasionally returns
176 read or write errors. It is useful for testing.
182 tristate "Cluster Support for MD"
183 depends on BLK_DEV_MD
187 Clustering support for MD devices. This enables locking and
188 synchronization across multiple systems on the cluster, so all
189 nodes in the cluster can access the MD devices simultaneously.
191 This brings the redundancy (and uptime) of RAID levels across the
192 nodes of the cluster. Currently, it can work with raid1 and raid10
197 source "drivers/md/bcache/Kconfig"
199 config BLK_DEV_DM_BUILTIN
203 tristate "Device mapper support"
204 select BLK_DEV_DM_BUILTIN
205 depends on DAX || DAX=n
207 Device-mapper is a low level volume manager. It works by allowing
208 people to specify mappings for ranges of logical sectors. Various
209 mapping types are available, in addition people may write their own
210 modules containing custom mappings if they wish.
212 Higher level volume managers such as LVM2 use this driver.
214 To compile this as a module, choose M here: the module will be
220 bool "Device mapper debugging support"
221 depends on BLK_DEV_DM
223 Enable this for messages that may help debug device-mapper problems.
229 depends on BLK_DEV_DM
231 This interface allows you to do buffered I/O on a device and acts
232 as a cache, holding recently-read blocks in memory and performing
235 config DM_DEBUG_BLOCK_MANAGER_LOCKING
236 bool "Block manager locking"
239 Block manager locking can catch various metadata corruption issues.
243 config DM_DEBUG_BLOCK_STACK_TRACING
244 bool "Keep stack trace of persistent data block lock holders"
245 depends on STACKTRACE_SUPPORT && DM_DEBUG_BLOCK_MANAGER_LOCKING
248 Enable this for messages that may help debug problems with the
249 block manager locking used by thin provisioning and caching.
255 depends on BLK_DEV_DM
257 Some bio locking schemes used by other device-mapper targets
258 including thin provisioning.
260 source "drivers/md/persistent-data/Kconfig"
263 tristate "Unstriped target"
264 depends on BLK_DEV_DM
266 Unstripes I/O so it is issued solely on a single drive in a HW
267 RAID0 or dm-striped target.
270 tristate "Crypt target support"
271 depends on BLK_DEV_DM
275 This device-mapper target allows you to create a device that
276 transparently encrypts the data on it. You'll need to activate
277 the ciphers you're going to use in the cryptoapi configuration.
279 For further information on dm-crypt and userspace tools see:
280 <https://gitlab.com/cryptsetup/cryptsetup/wikis/DMCrypt>
282 To compile this code as a module, choose M here: the module will
288 tristate "Snapshot target"
289 depends on BLK_DEV_DM
292 Allow volume managers to take writable snapshots of a device.
294 config DM_THIN_PROVISIONING
295 tristate "Thin provisioning target"
296 depends on BLK_DEV_DM
297 select DM_PERSISTENT_DATA
300 Provides thin provisioning and snapshots that share a data store.
303 tristate "Cache target (EXPERIMENTAL)"
304 depends on BLK_DEV_DM
306 select DM_PERSISTENT_DATA
309 dm-cache attempts to improve performance of a block device by
310 moving frequently used data to a smaller, higher performance
311 device. Different 'policy' plugins can be used to change the
312 algorithms used to select which blocks are promoted, demoted,
313 cleaned etc. It supports writeback and writethrough modes.
316 tristate "Stochastic MQ Cache Policy (EXPERIMENTAL)"
320 A cache policy that uses a multiqueue ordered by recent hits
321 to select which blocks should be promoted and demoted.
322 This is meant to be a general purpose policy. It prioritises
323 reads over writes. This SMQ policy (vs MQ) offers the promise
324 of less memory utilization, improved performance and increased
325 adaptability in the face of changing workloads.
328 tristate "Writecache target"
329 depends on BLK_DEV_DM
331 The writecache target caches writes on persistent memory or SSD.
332 It is intended for databases or other programs that need extremely
335 The writecache target doesn't cache reads because reads are supposed
336 to be cached in standard RAM.
339 tristate "Era target (EXPERIMENTAL)"
340 depends on BLK_DEV_DM
342 select DM_PERSISTENT_DATA
345 dm-era tracks which parts of a block device are written to
346 over time. Useful for maintaining cache coherency when using
350 tristate "Mirror target"
351 depends on BLK_DEV_DM
353 Allow volume managers to mirror logical volumes, also
354 needed for live data migration tools such as 'pvmove'.
356 config DM_LOG_USERSPACE
357 tristate "Mirror userspace logging"
358 depends on DM_MIRROR && NET
361 The userspace logging module provides a mechanism for
362 relaying the dm-dirty-log API to userspace. Log designs
363 which are more suited to userspace implementation (e.g.
364 shared storage logs) or experimental logs can be implemented
365 by leveraging this framework.
368 tristate "RAID 1/4/5/6/10 target"
369 depends on BLK_DEV_DM
376 A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings
378 A RAID-5 set of N drives with a capacity of C MB per drive provides
379 the capacity of C * (N - 1) MB, and protects against a failure
380 of a single drive. For a given sector (row) number, (N - 1) drives
381 contain data sectors, and one drive contains the parity protection.
382 For a RAID-4 set, the parity blocks are present on a single drive,
383 while a RAID-5 set distributes the parity across the drives in one
384 of the available parity distribution methods.
386 A RAID-6 set of N drives with a capacity of C MB per drive
387 provides the capacity of C * (N - 2) MB, and protects
388 against a failure of any two drives. For a given sector
389 (row) number, (N - 2) drives contain data sectors, and two
390 drives contains two independent redundancy syndromes. Like
391 RAID-5, RAID-6 distributes the syndromes across the drives
392 in one of the available parity distribution methods.
395 tristate "Zero target"
396 depends on BLK_DEV_DM
398 A target that discards writes, and returns all zeroes for
399 reads. Useful in some recovery situations.
402 tristate "Multipath target"
403 depends on BLK_DEV_DM
404 # nasty syntax but means make DM_MULTIPATH independent
405 # of SCSI_DH if the latter isn't defined but if
406 # it is, DM_MULTIPATH must depend on it. We get a build
407 # error if SCSI_DH=m and DM_MULTIPATH=y
408 depends on !SCSI_DH || SCSI
410 Allow volume managers to support multipath hardware.
412 config DM_MULTIPATH_QL
413 tristate "I/O Path Selector based on the number of in-flight I/Os"
414 depends on DM_MULTIPATH
416 This path selector is a dynamic load balancer which selects
417 the path with the least number of in-flight I/Os.
421 config DM_MULTIPATH_ST
422 tristate "I/O Path Selector based on the service time"
423 depends on DM_MULTIPATH
425 This path selector is a dynamic load balancer which selects
426 the path expected to complete the incoming I/O in the shortest
432 tristate "I/O delaying target"
433 depends on BLK_DEV_DM
435 A target that delays reads and/or writes and can send
436 them to different devices. Useful for testing.
441 tristate "Bad sector simulation target"
442 depends on BLK_DEV_DM
444 A target that simulates bad sector behavior.
450 bool "DM \"dm-mod.create=\" parameter support"
451 depends on BLK_DEV_DM=y
453 Enable "dm-mod.create=" parameter to create mapped devices at init time.
454 This option is useful to allow mounting rootfs without requiring an
456 See Documentation/admin-guide/device-mapper/dm-init.rst for dm-mod.create="..."
463 depends on BLK_DEV_DM
465 Generate udev events for DM events.
468 tristate "Flakey target"
469 depends on BLK_DEV_DM
471 A target that intermittently fails I/O for debugging purposes.
474 tristate "Verity target support"
475 depends on BLK_DEV_DM
480 This device-mapper target creates a read-only device that
481 transparently validates the data on one underlying device against
482 a pre-generated tree of cryptographic checksums stored on a second
485 You'll need to activate the digests you're going to use in the
486 cryptoapi configuration.
488 To compile this code as a module, choose M here: the module will
494 bool "Verity forward error correction support"
497 select REED_SOLOMON_DEC8
499 Add forward error correction support to dm-verity. This option
500 makes it possible to use pre-generated error correction data to
501 recover from corrupted blocks.
506 tristate "Switch target support (EXPERIMENTAL)"
507 depends on BLK_DEV_DM
509 This device-mapper target creates a device that supports an arbitrary
510 mapping of fixed-size regions of I/O across a fixed set of paths.
511 The path used for any specific region can be switched dynamically
512 by sending the target a message.
514 To compile this code as a module, choose M here: the module will
520 tristate "Log writes target support"
521 depends on BLK_DEV_DM
523 This device-mapper target takes two devices, one device to use
524 normally, one to log all write operations done to the first device.
525 This is for use by file system developers wishing to verify that
526 their fs is writing a consistent file system at all times by allowing
527 them to replay the log in a variety of ways and to check the
530 To compile this code as a module, choose M here: the module will
531 be called dm-log-writes.
536 tristate "Integrity target support"
537 depends on BLK_DEV_DM
538 select BLK_DEV_INTEGRITY
543 This device-mapper target emulates a block device that has
544 additional per-sector tags that can be used for storing
545 integrity information.
547 This integrity target is used with the dm-crypt target to
548 provide authenticated disk encryption or it can be used
551 To compile this code as a module, choose M here: the module will
552 be called dm-integrity.
555 tristate "Drive-managed zoned block device target support"
556 depends on BLK_DEV_DM
557 depends on BLK_DEV_ZONED
559 This device-mapper target takes a host-managed or host-aware zoned
560 block device and exposes most of its capacity as a regular block
561 device (drive-managed zoned block device) without any write
562 constraints. This is mainly intended for use with file systems that
563 do not natively support zoned block devices but still want to
564 benefit from the increased capacity offered by SMR disks. Other uses
565 by applications using raw block devices (for example object stores)
568 To compile this code as a module, choose M here: the module will