2 # Block device driver configuration
6 bool "Multiple devices driver support (RAID and LVM)"
9 Support multiple physical spindles through a single logical device.
10 Required for RAID and logical volume management.
15 tristate "RAID support"
17 This driver lets you combine several hard disk partitions into one
18 logical block device. This can be used to simply append one
19 partition to another one or to combine several redundant hard disks
20 into a RAID1/4/5 device so as to provide protection against hard
21 disk failures. This is called "Software RAID" since the combining of
22 the partitions is done by the kernel. "Hardware RAID" means that the
23 combining is done by a dedicated controller; if you have such a
24 controller, you do not need to say Y here.
26 More information about Software RAID on Linux is contained in the
27 Software RAID mini-HOWTO, available from
28 <http://www.tldp.org/docs.html#howto>. There you will also learn
29 where to get the supporting user space utilities raidtools.
34 bool "Autodetect RAID arrays during kernel boot"
35 depends on BLK_DEV_MD=y
38 If you say Y here, then the kernel will try to autodetect raid
39 arrays as part of its boot process.
41 If you don't use raid and say Y, this autodetection can cause
42 a several-second delay in the boot time due to various
43 synchronisation steps that are part of this step.
48 tristate "Linear (append) mode"
51 If you say Y here, then your multiple devices driver will be able to
52 use the so-called linear mode, i.e. it will combine the hard disk
53 partitions by simply appending one to the other.
55 To compile this as a module, choose M here: the module
56 will be called linear.
61 tristate "RAID-0 (striping) mode"
64 If you say Y here, then your multiple devices driver will be able to
65 use the so-called raid0 mode, i.e. it will combine the hard disk
66 partitions into one logical device in such a fashion as to fill them
67 up evenly, one chunk here and one chunk there. This will increase
68 the throughput rate if the partitions reside on distinct disks.
70 Information about Software RAID on Linux is contained in the
71 Software-RAID mini-HOWTO, available from
72 <http://www.tldp.org/docs.html#howto>. There you will also
73 learn where to get the supporting user space utilities raidtools.
75 To compile this as a module, choose M here: the module
81 tristate "RAID-1 (mirroring) mode"
84 A RAID-1 set consists of several disk drives which are exact copies
85 of each other. In the event of a mirror failure, the RAID driver
86 will continue to use the operational mirrors in the set, providing
87 an error free MD (multiple device) to the higher levels of the
88 kernel. In a set with N drives, the available space is the capacity
89 of a single drive, and the set protects against a failure of (N - 1)
92 Information about Software RAID on Linux is contained in the
93 Software-RAID mini-HOWTO, available from
94 <http://www.tldp.org/docs.html#howto>. There you will also
95 learn where to get the supporting user space utilities raidtools.
97 If you want to use such a RAID-1 set, say Y. To compile this code
98 as a module, choose M here: the module will be called raid1.
103 tristate "RAID-10 (mirrored striping) mode"
104 depends on BLK_DEV_MD
106 RAID-10 provides a combination of striping (RAID-0) and
107 mirroring (RAID-1) with easier configuration and more flexible
109 Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to
110 be the same size (or at least, only as much as the smallest device
112 RAID-10 provides a variety of layouts that provide different levels
113 of redundancy and performance.
115 RAID-10 requires mdadm-1.7.0 or later, available at:
117 ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/
122 tristate "RAID-4/RAID-5/RAID-6 mode"
123 depends on BLK_DEV_MD
128 select ASYNC_RAID6_RECOV
130 A RAID-5 set of N drives with a capacity of C MB per drive provides
131 the capacity of C * (N - 1) MB, and protects against a failure
132 of a single drive. For a given sector (row) number, (N - 1) drives
133 contain data sectors, and one drive contains the parity protection.
134 For a RAID-4 set, the parity blocks are present on a single drive,
135 while a RAID-5 set distributes the parity across the drives in one
136 of the available parity distribution methods.
138 A RAID-6 set of N drives with a capacity of C MB per drive
139 provides the capacity of C * (N - 2) MB, and protects
140 against a failure of any two drives. For a given sector
141 (row) number, (N - 2) drives contain data sectors, and two
142 drives contains two independent redundancy syndromes. Like
143 RAID-5, RAID-6 distributes the syndromes across the drives
144 in one of the available parity distribution methods.
146 Information about Software RAID on Linux is contained in the
147 Software-RAID mini-HOWTO, available from
148 <http://www.tldp.org/docs.html#howto>. There you will also
149 learn where to get the supporting user space utilities raidtools.
151 If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To
152 compile this code as a module, choose M here: the module
153 will be called raid456.
158 tristate "Multipath I/O support"
159 depends on BLK_DEV_MD
161 MD_MULTIPATH provides a simple multi-path personality for use
162 the MD framework. It is not under active development. New
163 projects should consider using DM_MULTIPATH which has more
164 features and more testing.
169 tristate "Faulty test module for MD"
170 depends on BLK_DEV_MD
172 The "faulty" module allows for a block device that occasionally returns
173 read or write errors. It is useful for testing.
178 tristate "Device mapper support"
180 Device-mapper is a low level volume manager. It works by allowing
181 people to specify mappings for ranges of logical sectors. Various
182 mapping types are available, in addition people may write their own
183 modules containing custom mappings if they wish.
185 Higher level volume managers such as LVM2 use this driver.
187 To compile this as a module, choose M here: the module will be
193 boolean "Device mapper debugging support"
194 depends on BLK_DEV_DM
196 Enable this for messages that may help debug device-mapper problems.
202 depends on BLK_DEV_DM && EXPERIMENTAL
204 This interface allows you to do buffered I/O on a device and acts
205 as a cache, holding recently-read blocks in memory and performing
210 depends on BLK_DEV_DM && EXPERIMENTAL
212 Some bio locking schemes used by other device-mapper targets
213 including thin provisioning.
215 source "drivers/md/persistent-data/Kconfig"
218 tristate "Crypt target support"
219 depends on BLK_DEV_DM
223 This device-mapper target allows you to create a device that
224 transparently encrypts the data on it. You'll need to activate
225 the ciphers you're going to use in the cryptoapi configuration.
227 Information on how to use dm-crypt can be found on
229 <http://www.saout.de/misc/dm-crypt/>
231 To compile this code as a module, choose M here: the module will
237 tristate "Snapshot target"
238 depends on BLK_DEV_DM
240 Allow volume managers to take writable snapshots of a device.
242 config DM_THIN_PROVISIONING
243 tristate "Thin provisioning target (EXPERIMENTAL)"
244 depends on BLK_DEV_DM && EXPERIMENTAL
245 select DM_PERSISTENT_DATA
248 Provides thin provisioning and snapshots that share a data store.
250 config DM_DEBUG_BLOCK_STACK_TRACING
251 boolean "Keep stack trace of thin provisioning block lock holders"
252 depends on STACKTRACE_SUPPORT && DM_THIN_PROVISIONING
255 Enable this for messages that may help debug problems with the
256 block manager locking used by thin provisioning.
261 tristate "Mirror target"
262 depends on BLK_DEV_DM
264 Allow volume managers to mirror logical volumes, also
265 needed for live data migration tools such as 'pvmove'.
268 tristate "RAID 1/4/5/6/10 target"
269 depends on BLK_DEV_DM
275 A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings
277 A RAID-5 set of N drives with a capacity of C MB per drive provides
278 the capacity of C * (N - 1) MB, and protects against a failure
279 of a single drive. For a given sector (row) number, (N - 1) drives
280 contain data sectors, and one drive contains the parity protection.
281 For a RAID-4 set, the parity blocks are present on a single drive,
282 while a RAID-5 set distributes the parity across the drives in one
283 of the available parity distribution methods.
285 A RAID-6 set of N drives with a capacity of C MB per drive
286 provides the capacity of C * (N - 2) MB, and protects
287 against a failure of any two drives. For a given sector
288 (row) number, (N - 2) drives contain data sectors, and two
289 drives contains two independent redundancy syndromes. Like
290 RAID-5, RAID-6 distributes the syndromes across the drives
291 in one of the available parity distribution methods.
293 config DM_LOG_USERSPACE
294 tristate "Mirror userspace logging (EXPERIMENTAL)"
295 depends on DM_MIRROR && EXPERIMENTAL && NET
298 The userspace logging module provides a mechanism for
299 relaying the dm-dirty-log API to userspace. Log designs
300 which are more suited to userspace implementation (e.g.
301 shared storage logs) or experimental logs can be implemented
302 by leveraging this framework.
305 tristate "Zero target"
306 depends on BLK_DEV_DM
308 A target that discards writes, and returns all zeroes for
309 reads. Useful in some recovery situations.
312 tristate "Multipath target"
313 depends on BLK_DEV_DM
314 # nasty syntax but means make DM_MULTIPATH independent
315 # of SCSI_DH if the latter isn't defined but if
316 # it is, DM_MULTIPATH must depend on it. We get a build
317 # error if SCSI_DH=m and DM_MULTIPATH=y
318 depends on SCSI_DH || !SCSI_DH
320 Allow volume managers to support multipath hardware.
322 config DM_MULTIPATH_QL
323 tristate "I/O Path Selector based on the number of in-flight I/Os"
324 depends on DM_MULTIPATH
326 This path selector is a dynamic load balancer which selects
327 the path with the least number of in-flight I/Os.
331 config DM_MULTIPATH_ST
332 tristate "I/O Path Selector based on the service time"
333 depends on DM_MULTIPATH
335 This path selector is a dynamic load balancer which selects
336 the path expected to complete the incoming I/O in the shortest
342 tristate "I/O delaying target (EXPERIMENTAL)"
343 depends on BLK_DEV_DM && EXPERIMENTAL
345 A target that delays reads and/or writes and can send
346 them to different devices. Useful for testing.
352 depends on BLK_DEV_DM
354 Generate udev events for DM events.
357 tristate "Flakey target (EXPERIMENTAL)"
358 depends on BLK_DEV_DM && EXPERIMENTAL
360 A target that intermittently fails I/O for debugging purposes.
363 tristate "Verity target support (EXPERIMENTAL)"
364 depends on BLK_DEV_DM && EXPERIMENTAL
369 This device-mapper target creates a read-only device that
370 transparently validates the data on one underlying device against
371 a pre-generated tree of cryptographic checksums stored on a second
374 You'll need to activate the digests you're going to use in the
375 cryptoapi configuration.
377 To compile this code as a module, choose M here: the module will