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 https://www.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"
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. Currently, it can work with raid1 and raid10
196 source "drivers/md/bcache/Kconfig"
198 config BLK_DEV_DM_BUILTIN
202 tristate "Device mapper support"
203 select BLK_DEV_DM_BUILTIN
204 depends on DAX || DAX=n
206 Device-mapper is a low level volume manager. It works by allowing
207 people to specify mappings for ranges of logical sectors. Various
208 mapping types are available, in addition people may write their own
209 modules containing custom mappings if they wish.
211 Higher level volume managers such as LVM2 use this driver.
213 To compile this as a module, choose M here: the module will be
219 bool "Device mapper debugging support"
220 depends on BLK_DEV_DM
222 Enable this for messages that may help debug device-mapper problems.
228 depends on BLK_DEV_DM
230 This interface allows you to do buffered I/O on a device and acts
231 as a cache, holding recently-read blocks in memory and performing
234 config DM_DEBUG_BLOCK_MANAGER_LOCKING
235 bool "Block manager locking"
238 Block manager locking can catch various metadata corruption issues.
242 config DM_DEBUG_BLOCK_STACK_TRACING
243 bool "Keep stack trace of persistent data block lock holders"
244 depends on STACKTRACE_SUPPORT && DM_DEBUG_BLOCK_MANAGER_LOCKING
247 Enable this for messages that may help debug problems with the
248 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 "Unstriped target"
263 depends on BLK_DEV_DM
265 Unstripes I/O so it is issued solely on a single drive in a HW
266 RAID0 or dm-striped target.
269 tristate "Crypt target support"
270 depends on BLK_DEV_DM
274 This device-mapper target allows you to create a device that
275 transparently encrypts the data on it. You'll need to activate
276 the ciphers you're going to use in the cryptoapi configuration.
278 For further information on dm-crypt and userspace tools see:
279 <https://gitlab.com/cryptsetup/cryptsetup/wikis/DMCrypt>
281 To compile this code as a module, choose M here: the module will
287 tristate "Snapshot target"
288 depends on BLK_DEV_DM
291 Allow volume managers to take writable snapshots of a device.
293 config DM_THIN_PROVISIONING
294 tristate "Thin provisioning target"
295 depends on BLK_DEV_DM
296 select DM_PERSISTENT_DATA
299 Provides thin provisioning and snapshots that share a data store.
302 tristate "Cache target (EXPERIMENTAL)"
303 depends on BLK_DEV_DM
305 select DM_PERSISTENT_DATA
308 dm-cache attempts to improve performance of a block device by
309 moving frequently used data to a smaller, higher performance
310 device. Different 'policy' plugins can be used to change the
311 algorithms used to select which blocks are promoted, demoted,
312 cleaned etc. It supports writeback and writethrough modes.
315 tristate "Stochastic MQ Cache Policy (EXPERIMENTAL)"
319 A cache policy that uses a multiqueue ordered by recent hits
320 to select which blocks should be promoted and demoted.
321 This is meant to be a general purpose policy. It prioritises
322 reads over writes. This SMQ policy (vs MQ) offers the promise
323 of less memory utilization, improved performance and increased
324 adaptability in the face of changing workloads.
327 tristate "Writecache target"
328 depends on BLK_DEV_DM
330 The writecache target caches writes on persistent memory or SSD.
331 It is intended for databases or other programs that need extremely
334 The writecache target doesn't cache reads because reads are supposed
335 to be cached in standard RAM.
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
375 A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings
377 A RAID-5 set of N drives with a capacity of C MB per drive provides
378 the capacity of C * (N - 1) MB, and protects against a failure
379 of a single drive. For a given sector (row) number, (N - 1) drives
380 contain data sectors, and one drive contains the parity protection.
381 For a RAID-4 set, the parity blocks are present on a single drive,
382 while a RAID-5 set distributes the parity across the drives in one
383 of the available parity distribution methods.
385 A RAID-6 set of N drives with a capacity of C MB per drive
386 provides the capacity of C * (N - 2) MB, and protects
387 against a failure of any two drives. For a given sector
388 (row) number, (N - 2) drives contain data sectors, and two
389 drives contains two independent redundancy syndromes. Like
390 RAID-5, RAID-6 distributes the syndromes across the drives
391 in one of the available parity distribution methods.
394 tristate "Zero target"
395 depends on BLK_DEV_DM
397 A target that discards writes, and returns all zeroes for
398 reads. Useful in some recovery situations.
401 tristate "Multipath target"
402 depends on BLK_DEV_DM
403 # nasty syntax but means make DM_MULTIPATH independent
404 # of SCSI_DH if the latter isn't defined but if
405 # it is, DM_MULTIPATH must depend on it. We get a build
406 # error if SCSI_DH=m and DM_MULTIPATH=y
407 depends on !SCSI_DH || SCSI
409 Allow volume managers to support multipath hardware.
411 config DM_MULTIPATH_QL
412 tristate "I/O Path Selector based on the number of in-flight I/Os"
413 depends on DM_MULTIPATH
415 This path selector is a dynamic load balancer which selects
416 the path with the least number of in-flight I/Os.
420 config DM_MULTIPATH_ST
421 tristate "I/O Path Selector based on the service time"
422 depends on DM_MULTIPATH
424 This path selector is a dynamic load balancer which selects
425 the path expected to complete the incoming I/O in the shortest
431 tristate "I/O delaying target"
432 depends on BLK_DEV_DM
434 A target that delays reads and/or writes and can send
435 them to different devices. Useful for testing.
440 bool "DM \"dm-mod.create=\" parameter support"
441 depends on BLK_DEV_DM=y
443 Enable "dm-mod.create=" parameter to create mapped devices at init time.
444 This option is useful to allow mounting rootfs without requiring an
446 See Documentation/device-mapper/dm-init.txt for dm-mod.create="..."
453 depends on BLK_DEV_DM
455 Generate udev events for DM events.
458 tristate "Flakey target"
459 depends on BLK_DEV_DM
461 A target that intermittently fails I/O for debugging purposes.
464 tristate "Verity target support"
465 depends on BLK_DEV_DM
470 This device-mapper target creates a read-only device that
471 transparently validates the data on one underlying device against
472 a pre-generated tree of cryptographic checksums stored on a second
475 You'll need to activate the digests you're going to use in the
476 cryptoapi configuration.
478 To compile this code as a module, choose M here: the module will
484 bool "Verity forward error correction support"
487 select REED_SOLOMON_DEC8
489 Add forward error correction support to dm-verity. This option
490 makes it possible to use pre-generated error correction data to
491 recover from corrupted blocks.
496 tristate "Switch target support (EXPERIMENTAL)"
497 depends on BLK_DEV_DM
499 This device-mapper target creates a device that supports an arbitrary
500 mapping of fixed-size regions of I/O across a fixed set of paths.
501 The path used for any specific region can be switched dynamically
502 by sending the target a message.
504 To compile this code as a module, choose M here: the module will
510 tristate "Log writes target support"
511 depends on BLK_DEV_DM
513 This device-mapper target takes two devices, one device to use
514 normally, one to log all write operations done to the first device.
515 This is for use by file system developers wishing to verify that
516 their fs is writing a consistent file system at all times by allowing
517 them to replay the log in a variety of ways and to check the
520 To compile this code as a module, choose M here: the module will
521 be called dm-log-writes.
526 tristate "Integrity target support"
527 depends on BLK_DEV_DM
528 select BLK_DEV_INTEGRITY
533 This device-mapper target emulates a block device that has
534 additional per-sector tags that can be used for storing
535 integrity information.
537 This integrity target is used with the dm-crypt target to
538 provide authenticated disk encryption or it can be used
541 To compile this code as a module, choose M here: the module will
542 be called dm-integrity.
545 tristate "Drive-managed zoned block device target support"
546 depends on BLK_DEV_DM
547 depends on BLK_DEV_ZONED
549 This device-mapper target takes a host-managed or host-aware zoned
550 block device and exposes most of its capacity as a regular block
551 device (drive-managed zoned block device) without any write
552 constraints. This is mainly intended for use with file systems that
553 do not natively support zoned block devices but still want to
554 benefit from the increased capacity offered by SMR disks. Other uses
555 by applications using raw block devices (for example object stores)
558 To compile this code as a module, choose M here: the module will