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
129 select ASYNC_RAID6_RECOV
131 A RAID-5 set of N drives with a capacity of C MB per drive provides
132 the capacity of C * (N - 1) MB, and protects against a failure
133 of a single drive. For a given sector (row) number, (N - 1) drives
134 contain data sectors, and one drive contains the parity protection.
135 For a RAID-4 set, the parity blocks are present on a single drive,
136 while a RAID-5 set distributes the parity across the drives in one
137 of the available parity distribution methods.
139 A RAID-6 set of N drives with a capacity of C MB per drive
140 provides the capacity of C * (N - 2) MB, and protects
141 against a failure of any two drives. For a given sector
142 (row) number, (N - 2) drives contain data sectors, and two
143 drives contains two independent redundancy syndromes. Like
144 RAID-5, RAID-6 distributes the syndromes across the drives
145 in one of the available parity distribution methods.
147 Information about Software RAID on Linux is contained in the
148 Software-RAID mini-HOWTO, available from
149 <http://www.tldp.org/docs.html#howto>. There you will also
150 learn where to get the supporting user space utilities raidtools.
152 If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To
153 compile this code as a module, choose M here: the module
154 will be called raid456.
159 tristate "Multipath I/O support"
160 depends on BLK_DEV_MD
162 MD_MULTIPATH provides a simple multi-path personality for use
163 the MD framework. It is not under active development. New
164 projects should consider using DM_MULTIPATH which has more
165 features and more testing.
170 tristate "Faulty test module for MD"
171 depends on BLK_DEV_MD
173 The "faulty" module allows for a block device that occasionally returns
174 read or write errors. It is useful for testing.
180 tristate "Cluster Support for MD (EXPERIMENTAL)"
181 depends on BLK_DEV_MD
185 Clustering support for MD devices. This enables locking and
186 synchronization across multiple systems on the cluster, so all
187 nodes in the cluster can access the MD devices simultaneously.
189 This brings the redundancy (and uptime) of RAID levels across the
190 nodes of the cluster.
194 source "drivers/md/bcache/Kconfig"
196 config BLK_DEV_DM_BUILTIN
200 tristate "Device mapper support"
201 select BLK_DEV_DM_BUILTIN
203 Device-mapper is a low level volume manager. It works by allowing
204 people to specify mappings for ranges of logical sectors. Various
205 mapping types are available, in addition people may write their own
206 modules containing custom mappings if they wish.
208 Higher level volume managers such as LVM2 use this driver.
210 To compile this as a module, choose M here: the module will be
216 bool "request-based DM: use blk-mq I/O path by default"
217 depends on BLK_DEV_DM
219 This option enables the blk-mq based I/O path for request-based
220 DM devices by default. With the option the dm_mod.use_blk_mq
221 module/boot option defaults to Y, without it to N, but it can
222 still be overriden either way.
227 bool "Device mapper debugging support"
228 depends on BLK_DEV_DM
230 Enable this for messages that may help debug device-mapper problems.
236 depends on BLK_DEV_DM
238 This interface allows you to do buffered I/O on a device and acts
239 as a cache, holding recently-read blocks in memory and performing
244 depends on BLK_DEV_DM
246 Some bio locking schemes used by other device-mapper targets
247 including thin provisioning.
249 source "drivers/md/persistent-data/Kconfig"
252 tristate "Crypt target support"
253 depends on BLK_DEV_DM
257 This device-mapper target allows you to create a device that
258 transparently encrypts the data on it. You'll need to activate
259 the ciphers you're going to use in the cryptoapi configuration.
261 For further information on dm-crypt and userspace tools see:
262 <https://gitlab.com/cryptsetup/cryptsetup/wikis/DMCrypt>
264 To compile this code as a module, choose M here: the module will
270 tristate "Snapshot target"
271 depends on BLK_DEV_DM
274 Allow volume managers to take writable snapshots of a device.
276 config DM_THIN_PROVISIONING
277 tristate "Thin provisioning target"
278 depends on BLK_DEV_DM
279 select DM_PERSISTENT_DATA
282 Provides thin provisioning and snapshots that share a data store.
285 tristate "Cache target (EXPERIMENTAL)"
286 depends on BLK_DEV_DM
288 select DM_PERSISTENT_DATA
291 dm-cache attempts to improve performance of a block device by
292 moving frequently used data to a smaller, higher performance
293 device. Different 'policy' plugins can be used to change the
294 algorithms used to select which blocks are promoted, demoted,
295 cleaned etc. It supports writeback and writethrough modes.
298 tristate "MQ Cache Policy (EXPERIMENTAL)"
302 A cache policy that uses a multiqueue ordered by recent hit
303 count to select which blocks should be promoted and demoted.
304 This is meant to be a general purpose policy. It prioritises
308 tristate "Stochastic MQ Cache Policy (EXPERIMENTAL)"
312 A cache policy that uses a multiqueue ordered by recent hits
313 to select which blocks should be promoted and demoted.
314 This is meant to be a general purpose policy. It prioritises
315 reads over writes. This SMQ policy (vs MQ) offers the promise
316 of less memory utilization, improved performance and increased
317 adaptability in the face of changing workloads.
319 config DM_CACHE_CLEANER
320 tristate "Cleaner Cache Policy (EXPERIMENTAL)"
324 A simple cache policy that writes back all data to the
325 origin. Used when decommissioning a dm-cache.
328 tristate "Era target (EXPERIMENTAL)"
329 depends on BLK_DEV_DM
331 select DM_PERSISTENT_DATA
334 dm-era tracks which parts of a block device are written to
335 over time. Useful for maintaining cache coherency when using
339 tristate "Mirror target"
340 depends on BLK_DEV_DM
342 Allow volume managers to mirror logical volumes, also
343 needed for live data migration tools such as 'pvmove'.
345 config DM_LOG_USERSPACE
346 tristate "Mirror userspace logging"
347 depends on DM_MIRROR && NET
350 The userspace logging module provides a mechanism for
351 relaying the dm-dirty-log API to userspace. Log designs
352 which are more suited to userspace implementation (e.g.
353 shared storage logs) or experimental logs can be implemented
354 by leveraging this framework.
357 tristate "RAID 1/4/5/6/10 target"
358 depends on BLK_DEV_DM
364 A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings
366 A RAID-5 set of N drives with a capacity of C MB per drive provides
367 the capacity of C * (N - 1) MB, and protects against a failure
368 of a single drive. For a given sector (row) number, (N - 1) drives
369 contain data sectors, and one drive contains the parity protection.
370 For a RAID-4 set, the parity blocks are present on a single drive,
371 while a RAID-5 set distributes the parity across the drives in one
372 of the available parity distribution methods.
374 A RAID-6 set of N drives with a capacity of C MB per drive
375 provides the capacity of C * (N - 2) MB, and protects
376 against a failure of any two drives. For a given sector
377 (row) number, (N - 2) drives contain data sectors, and two
378 drives contains two independent redundancy syndromes. Like
379 RAID-5, RAID-6 distributes the syndromes across the drives
380 in one of the available parity distribution methods.
383 tristate "Zero target"
384 depends on BLK_DEV_DM
386 A target that discards writes, and returns all zeroes for
387 reads. Useful in some recovery situations.
390 tristate "Multipath target"
391 depends on BLK_DEV_DM
392 # nasty syntax but means make DM_MULTIPATH independent
393 # of SCSI_DH if the latter isn't defined but if
394 # it is, DM_MULTIPATH must depend on it. We get a build
395 # error if SCSI_DH=m and DM_MULTIPATH=y
396 depends on !SCSI_DH || SCSI
398 Allow volume managers to support multipath hardware.
400 config DM_MULTIPATH_QL
401 tristate "I/O Path Selector based on the number of in-flight I/Os"
402 depends on DM_MULTIPATH
404 This path selector is a dynamic load balancer which selects
405 the path with the least number of in-flight I/Os.
409 config DM_MULTIPATH_ST
410 tristate "I/O Path Selector based on the service time"
411 depends on DM_MULTIPATH
413 This path selector is a dynamic load balancer which selects
414 the path expected to complete the incoming I/O in the shortest
420 tristate "I/O delaying target"
421 depends on BLK_DEV_DM
423 A target that delays reads and/or writes and can send
424 them to different devices. Useful for testing.
430 depends on BLK_DEV_DM
432 Generate udev events for DM events.
435 tristate "Flakey target"
436 depends on BLK_DEV_DM
438 A target that intermittently fails I/O for debugging purposes.
441 tristate "Verity target support"
442 depends on BLK_DEV_DM
447 This device-mapper target creates a read-only device that
448 transparently validates the data on one underlying device against
449 a pre-generated tree of cryptographic checksums stored on a second
452 You'll need to activate the digests you're going to use in the
453 cryptoapi configuration.
455 To compile this code as a module, choose M here: the module will
461 tristate "Switch target support (EXPERIMENTAL)"
462 depends on BLK_DEV_DM
464 This device-mapper target creates a device that supports an arbitrary
465 mapping of fixed-size regions of I/O across a fixed set of paths.
466 The path used for any specific region can be switched dynamically
467 by sending the target a message.
469 To compile this code as a module, choose M here: the module will
475 tristate "Log writes target support"
476 depends on BLK_DEV_DM
478 This device-mapper target takes two devices, one device to use
479 normally, one to log all write operations done to the first device.
480 This is for use by file system developers wishing to verify that
481 their fs is writing a consistent file system at all times by allowing
482 them to replay the log in a variety of ways and to check the
485 To compile this code as a module, choose M here: the module will
486 be called dm-log-writes.