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.
178 source "drivers/md/bcache/Kconfig"
180 config BLK_DEV_DM_BUILTIN
184 tristate "Device mapper support"
185 select BLK_DEV_DM_BUILTIN
187 Device-mapper is a low level volume manager. It works by allowing
188 people to specify mappings for ranges of logical sectors. Various
189 mapping types are available, in addition people may write their own
190 modules containing custom mappings if they wish.
192 Higher level volume managers such as LVM2 use this driver.
194 To compile this as a module, choose M here: the module will be
200 boolean "Device mapper debugging support"
201 depends on BLK_DEV_DM
203 Enable this for messages that may help debug device-mapper problems.
209 depends on BLK_DEV_DM
211 This interface allows you to do buffered I/O on a device and acts
212 as a cache, holding recently-read blocks in memory and performing
217 depends on BLK_DEV_DM
219 Some bio locking schemes used by other device-mapper targets
220 including thin provisioning.
222 source "drivers/md/persistent-data/Kconfig"
225 tristate "Crypt target support"
226 depends on BLK_DEV_DM
230 This device-mapper target allows you to create a device that
231 transparently encrypts the data on it. You'll need to activate
232 the ciphers you're going to use in the cryptoapi configuration.
234 Information on how to use dm-crypt can be found on
236 <http://www.saout.de/misc/dm-crypt/>
238 To compile this code as a module, choose M here: the module will
244 tristate "Snapshot target"
245 depends on BLK_DEV_DM
248 Allow volume managers to take writable snapshots of a device.
250 config DM_THIN_PROVISIONING
251 tristate "Thin provisioning target"
252 depends on BLK_DEV_DM
253 select DM_PERSISTENT_DATA
256 Provides thin provisioning and snapshots that share a data store.
259 tristate "Cache target (EXPERIMENTAL)"
260 depends on BLK_DEV_DM
262 select DM_PERSISTENT_DATA
265 dm-cache attempts to improve performance of a block device by
266 moving frequently used data to a smaller, higher performance
267 device. Different 'policy' plugins can be used to change the
268 algorithms used to select which blocks are promoted, demoted,
269 cleaned etc. It supports writeback and writethrough modes.
272 tristate "MQ Cache Policy (EXPERIMENTAL)"
276 A cache policy that uses a multiqueue ordered by recent hit
277 count to select which blocks should be promoted and demoted.
278 This is meant to be a general purpose policy. It prioritises
281 config DM_CACHE_CLEANER
282 tristate "Cleaner Cache Policy (EXPERIMENTAL)"
286 A simple cache policy that writes back all data to the
287 origin. Used when decommissioning a dm-cache.
290 tristate "Era target (EXPERIMENTAL)"
291 depends on BLK_DEV_DM
293 select DM_PERSISTENT_DATA
296 dm-era tracks which parts of a block device are written to
297 over time. Useful for maintaining cache coherency when using
301 tristate "Mirror target"
302 depends on BLK_DEV_DM
304 Allow volume managers to mirror logical volumes, also
305 needed for live data migration tools such as 'pvmove'.
307 config DM_LOG_USERSPACE
308 tristate "Mirror userspace logging"
309 depends on DM_MIRROR && NET
312 The userspace logging module provides a mechanism for
313 relaying the dm-dirty-log API to userspace. Log designs
314 which are more suited to userspace implementation (e.g.
315 shared storage logs) or experimental logs can be implemented
316 by leveraging this framework.
319 tristate "RAID 1/4/5/6/10 target"
320 depends on BLK_DEV_DM
326 A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings
328 A RAID-5 set of N drives with a capacity of C MB per drive provides
329 the capacity of C * (N - 1) MB, and protects against a failure
330 of a single drive. For a given sector (row) number, (N - 1) drives
331 contain data sectors, and one drive contains the parity protection.
332 For a RAID-4 set, the parity blocks are present on a single drive,
333 while a RAID-5 set distributes the parity across the drives in one
334 of the available parity distribution methods.
336 A RAID-6 set of N drives with a capacity of C MB per drive
337 provides the capacity of C * (N - 2) MB, and protects
338 against a failure of any two drives. For a given sector
339 (row) number, (N - 2) drives contain data sectors, and two
340 drives contains two independent redundancy syndromes. Like
341 RAID-5, RAID-6 distributes the syndromes across the drives
342 in one of the available parity distribution methods.
345 tristate "Zero target"
346 depends on BLK_DEV_DM
348 A target that discards writes, and returns all zeroes for
349 reads. Useful in some recovery situations.
352 tristate "Multipath target"
353 depends on BLK_DEV_DM
354 # nasty syntax but means make DM_MULTIPATH independent
355 # of SCSI_DH if the latter isn't defined but if
356 # it is, DM_MULTIPATH must depend on it. We get a build
357 # error if SCSI_DH=m and DM_MULTIPATH=y
358 depends on SCSI_DH || !SCSI_DH
360 Allow volume managers to support multipath hardware.
362 config DM_MULTIPATH_QL
363 tristate "I/O Path Selector based on the number of in-flight I/Os"
364 depends on DM_MULTIPATH
366 This path selector is a dynamic load balancer which selects
367 the path with the least number of in-flight I/Os.
371 config DM_MULTIPATH_ST
372 tristate "I/O Path Selector based on the service time"
373 depends on DM_MULTIPATH
375 This path selector is a dynamic load balancer which selects
376 the path expected to complete the incoming I/O in the shortest
382 tristate "I/O delaying target"
383 depends on BLK_DEV_DM
385 A target that delays reads and/or writes and can send
386 them to different devices. Useful for testing.
392 depends on BLK_DEV_DM
394 Generate udev events for DM events.
397 tristate "Flakey target"
398 depends on BLK_DEV_DM
400 A target that intermittently fails I/O for debugging purposes.
403 tristate "Verity target support"
404 depends on BLK_DEV_DM
409 This device-mapper target creates a read-only device that
410 transparently validates the data on one underlying device against
411 a pre-generated tree of cryptographic checksums stored on a second
414 You'll need to activate the digests you're going to use in the
415 cryptoapi configuration.
417 To compile this code as a module, choose M here: the module will
423 tristate "Switch target support (EXPERIMENTAL)"
424 depends on BLK_DEV_DM
426 This device-mapper target creates a device that supports an arbitrary
427 mapping of fixed-size regions of I/O across a fixed set of paths.
428 The path used for any specific region can be switched dynamically
429 by sending the target a message.
431 To compile this code as a module, choose M here: the module will