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1#
2# Block device driver configuration
3#
4
5menuconfig MD
6 bool "Multiple devices driver support (RAID and LVM)"
7 depends on BLOCK
8 help
9 Support multiple physical spindles through a single logical device.
10 Required for RAID and logical volume management.
11
12if MD
13
14config BLK_DEV_MD
15 tristate "RAID support"
16 ---help---
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.
25
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.
30
31 If unsure, say N.
32
33config MD_AUTODETECT
34 bool "Autodetect RAID arrays during kernel boot"
35 depends on BLK_DEV_MD=y
36 default y
37 ---help---
38 If you say Y here, then the kernel will try to autodetect raid
39 arrays as part of its boot process.
40
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.
44
45 If unsure, say Y.
46
47config MD_LINEAR
48 tristate "Linear (append) mode"
49 depends on BLK_DEV_MD
50 ---help---
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.
54
55 To compile this as a module, choose M here: the module
56 will be called linear.
57
58 If unsure, say Y.
59
60config MD_RAID0
61 tristate "RAID-0 (striping) mode"
62 depends on BLK_DEV_MD
63 ---help---
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.
69
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.
74
75 To compile this as a module, choose M here: the module
76 will be called raid0.
77
78 If unsure, say Y.
79
80config MD_RAID1
81 tristate "RAID-1 (mirroring) mode"
82 depends on BLK_DEV_MD
83 ---help---
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)
90 drives.
91
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.
96
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.
99
100 If unsure, say Y.
101
102config MD_RAID10
103 tristate "RAID-10 (mirrored striping) mode"
104 depends on BLK_DEV_MD
105 ---help---
106 RAID-10 provides a combination of striping (RAID-0) and
107 mirroring (RAID-1) with easier configuration and more flexible
108 layout.
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
111 will be used).
112 RAID-10 provides a variety of layouts that provide different levels
113 of redundancy and performance.
114
115 RAID-10 requires mdadm-1.7.0 or later, available at:
116
117 ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/
118
119 If unsure, say Y.
120
121config MD_RAID456
122 tristate "RAID-4/RAID-5/RAID-6 mode"
123 depends on BLK_DEV_MD
124 select RAID6_PQ
125 select ASYNC_MEMCPY
126 select ASYNC_XOR
127 select ASYNC_PQ
128 select ASYNC_RAID6_RECOV
129 ---help---
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.
137
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.
145
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.
150
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.
154
155 If unsure, say Y.
156
157config MULTICORE_RAID456
158 bool "RAID-4/RAID-5/RAID-6 Multicore processing (EXPERIMENTAL)"
159 depends on MD_RAID456
160 depends on SMP
161 depends on EXPERIMENTAL
162 ---help---
163 Enable the raid456 module to dispatch per-stripe raid operations to a
164 thread pool.
165
166 If unsure, say N.
167
168config MD_MULTIPATH
169 tristate "Multipath I/O support"
170 depends on BLK_DEV_MD
171 help
172 MD_MULTIPATH provides a simple multi-path personality for use
173 the MD framework. It is not under active development. New
174 projects should consider using DM_MULTIPATH which has more
175 features and more testing.
176
177 If unsure, say N.
178
179config MD_FAULTY
180 tristate "Faulty test module for MD"
181 depends on BLK_DEV_MD
182 help
183 The "faulty" module allows for a block device that occasionally returns
184 read or write errors. It is useful for testing.
185
186 In unsure, say N.
187
188config BLK_DEV_DM
189 tristate "Device mapper support"
190 ---help---
191 Device-mapper is a low level volume manager. It works by allowing
192 people to specify mappings for ranges of logical sectors. Various
193 mapping types are available, in addition people may write their own
194 modules containing custom mappings if they wish.
195
196 Higher level volume managers such as LVM2 use this driver.
197
198 To compile this as a module, choose M here: the module will be
199 called dm-mod.
200
201 If unsure, say N.
202
203config DM_DEBUG
204 boolean "Device mapper debugging support"
205 depends on BLK_DEV_DM
206 ---help---
207 Enable this for messages that may help debug device-mapper problems.
208
209 If unsure, say N.
210
211config DM_BUFIO
212 tristate
213 depends on BLK_DEV_DM && EXPERIMENTAL
214 ---help---
215 This interface allows you to do buffered I/O on a device and acts
216 as a cache, holding recently-read blocks in memory and performing
217 delayed writes.
218
219source "drivers/md/persistent-data/Kconfig"
220
221config DM_CRYPT
222 tristate "Crypt target support"
223 depends on BLK_DEV_DM
224 select CRYPTO
225 select CRYPTO_CBC
226 ---help---
227 This device-mapper target allows you to create a device that
228 transparently encrypts the data on it. You'll need to activate
229 the ciphers you're going to use in the cryptoapi configuration.
230
231 Information on how to use dm-crypt can be found on
232
233 <http://www.saout.de/misc/dm-crypt/>
234
235 To compile this code as a module, choose M here: the module will
236 be called dm-crypt.
237
238 If unsure, say N.
239
240config DM_SNAPSHOT
241 tristate "Snapshot target"
242 depends on BLK_DEV_DM
243 ---help---
244 Allow volume managers to take writable snapshots of a device.
245
246config DM_THIN_PROVISIONING
247 tristate "Thin provisioning target (EXPERIMENTAL)"
248 depends on BLK_DEV_DM && EXPERIMENTAL
249 select DM_PERSISTENT_DATA
250 ---help---
251 Provides thin provisioning and snapshots that share a data store.
252
253config DM_DEBUG_BLOCK_STACK_TRACING
254 boolean "Keep stack trace of thin provisioning block lock holders"
255 depends on STACKTRACE_SUPPORT && DM_THIN_PROVISIONING
256 select STACKTRACE
257 ---help---
258 Enable this for messages that may help debug problems with the
259 block manager locking used by thin provisioning.
260
261 If unsure, say N.
262
263config DM_DEBUG_SPACE_MAPS
264 boolean "Extra validation for thin provisioning space maps"
265 depends on DM_THIN_PROVISIONING
266 ---help---
267 Enable this for messages that may help debug problems with the
268 space maps used by thin provisioning.
269
270 If unsure, say N.
271
272config DM_MIRROR
273 tristate "Mirror target"
274 depends on BLK_DEV_DM
275 ---help---
276 Allow volume managers to mirror logical volumes, also
277 needed for live data migration tools such as 'pvmove'.
278
279config DM_RAID
280 tristate "RAID 1/4/5/6 target"
281 depends on BLK_DEV_DM
282 select MD_RAID1
283 select MD_RAID456
284 select BLK_DEV_MD
285 ---help---
286 A dm target that supports RAID1, RAID4, RAID5 and RAID6 mappings
287
288 A RAID-5 set of N drives with a capacity of C MB per drive provides
289 the capacity of C * (N - 1) MB, and protects against a failure
290 of a single drive. For a given sector (row) number, (N - 1) drives
291 contain data sectors, and one drive contains the parity protection.
292 For a RAID-4 set, the parity blocks are present on a single drive,
293 while a RAID-5 set distributes the parity across the drives in one
294 of the available parity distribution methods.
295
296 A RAID-6 set of N drives with a capacity of C MB per drive
297 provides the capacity of C * (N - 2) MB, and protects
298 against a failure of any two drives. For a given sector
299 (row) number, (N - 2) drives contain data sectors, and two
300 drives contains two independent redundancy syndromes. Like
301 RAID-5, RAID-6 distributes the syndromes across the drives
302 in one of the available parity distribution methods.
303
304config DM_LOG_USERSPACE
305 tristate "Mirror userspace logging (EXPERIMENTAL)"
306 depends on DM_MIRROR && EXPERIMENTAL && NET
307 select CONNECTOR
308 ---help---
309 The userspace logging module provides a mechanism for
310 relaying the dm-dirty-log API to userspace. Log designs
311 which are more suited to userspace implementation (e.g.
312 shared storage logs) or experimental logs can be implemented
313 by leveraging this framework.
314
315config DM_ZERO
316 tristate "Zero target"
317 depends on BLK_DEV_DM
318 ---help---
319 A target that discards writes, and returns all zeroes for
320 reads. Useful in some recovery situations.
321
322config DM_MULTIPATH
323 tristate "Multipath target"
324 depends on BLK_DEV_DM
325 # nasty syntax but means make DM_MULTIPATH independent
326 # of SCSI_DH if the latter isn't defined but if
327 # it is, DM_MULTIPATH must depend on it. We get a build
328 # error if SCSI_DH=m and DM_MULTIPATH=y
329 depends on SCSI_DH || !SCSI_DH
330 ---help---
331 Allow volume managers to support multipath hardware.
332
333config DM_MULTIPATH_QL
334 tristate "I/O Path Selector based on the number of in-flight I/Os"
335 depends on DM_MULTIPATH
336 ---help---
337 This path selector is a dynamic load balancer which selects
338 the path with the least number of in-flight I/Os.
339
340 If unsure, say N.
341
342config DM_MULTIPATH_ST
343 tristate "I/O Path Selector based on the service time"
344 depends on DM_MULTIPATH
345 ---help---
346 This path selector is a dynamic load balancer which selects
347 the path expected to complete the incoming I/O in the shortest
348 time.
349
350 If unsure, say N.
351
352config DM_DELAY
353 tristate "I/O delaying target (EXPERIMENTAL)"
354 depends on BLK_DEV_DM && EXPERIMENTAL
355 ---help---
356 A target that delays reads and/or writes and can send
357 them to different devices. Useful for testing.
358
359 If unsure, say N.
360
361config DM_UEVENT
362 bool "DM uevents"
363 depends on BLK_DEV_DM
364 ---help---
365 Generate udev events for DM events.
366
367config DM_FLAKEY
368 tristate "Flakey target (EXPERIMENTAL)"
369 depends on BLK_DEV_DM && EXPERIMENTAL
370 ---help---
371 A target that intermittently fails I/O for debugging purposes.
372
373config DM_VERITY
374 tristate "Verity target support (EXPERIMENTAL)"
375 depends on BLK_DEV_DM && EXPERIMENTAL
376 select CRYPTO
377 select CRYPTO_HASH
378 select DM_BUFIO
379 ---help---
380 This device-mapper target creates a read-only device that
381 transparently validates the data on one underlying device against
382 a pre-generated tree of cryptographic checksums stored on a second
383 device.
384
385 You'll need to activate the digests you're going to use in the
386 cryptoapi configuration.
387
388 To compile this code as a module, choose M here: the module will
389 be called dm-verity.
390
391 If unsure, say N.
392
393endif # MD
1#
2# Block device driver configuration
3#
4
5menuconfig MD
6 bool "Multiple devices driver support (RAID and LVM)"
7 depends on BLOCK
8 select SRCU
9 help
10 Support multiple physical spindles through a single logical device.
11 Required for RAID and logical volume management.
12
13if MD
14
15config BLK_DEV_MD
16 tristate "RAID support"
17 ---help---
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.
26
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.
31
32 If unsure, say N.
33
34config MD_AUTODETECT
35 bool "Autodetect RAID arrays during kernel boot"
36 depends on BLK_DEV_MD=y
37 default y
38 ---help---
39 If you say Y here, then the kernel will try to autodetect raid
40 arrays as part of its boot process.
41
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.
45
46 If unsure, say Y.
47
48config MD_LINEAR
49 tristate "Linear (append) mode"
50 depends on BLK_DEV_MD
51 ---help---
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.
55
56 To compile this as a module, choose M here: the module
57 will be called linear.
58
59 If unsure, say Y.
60
61config MD_RAID0
62 tristate "RAID-0 (striping) mode"
63 depends on BLK_DEV_MD
64 ---help---
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.
70
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.
75
76 To compile this as a module, choose M here: the module
77 will be called raid0.
78
79 If unsure, say Y.
80
81config MD_RAID1
82 tristate "RAID-1 (mirroring) mode"
83 depends on BLK_DEV_MD
84 ---help---
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)
91 drives.
92
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.
97
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.
100
101 If unsure, say Y.
102
103config MD_RAID10
104 tristate "RAID-10 (mirrored striping) mode"
105 depends on BLK_DEV_MD
106 ---help---
107 RAID-10 provides a combination of striping (RAID-0) and
108 mirroring (RAID-1) with easier configuration and more flexible
109 layout.
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
112 will be used).
113 RAID-10 provides a variety of layouts that provide different levels
114 of redundancy and performance.
115
116 RAID-10 requires mdadm-1.7.0 or later, available at:
117
118 ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/
119
120 If unsure, say Y.
121
122config MD_RAID456
123 tristate "RAID-4/RAID-5/RAID-6 mode"
124 depends on BLK_DEV_MD
125 select RAID6_PQ
126 select LIBCRC32C
127 select ASYNC_MEMCPY
128 select ASYNC_XOR
129 select ASYNC_PQ
130 select ASYNC_RAID6_RECOV
131 ---help---
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.
139
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.
147
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.
152
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.
156
157 If unsure, say Y.
158
159config MD_MULTIPATH
160 tristate "Multipath I/O support"
161 depends on BLK_DEV_MD
162 help
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.
167
168 If unsure, say N.
169
170config MD_FAULTY
171 tristate "Faulty test module for MD"
172 depends on BLK_DEV_MD
173 help
174 The "faulty" module allows for a block device that occasionally returns
175 read or write errors. It is useful for testing.
176
177 In unsure, say N.
178
179
180config MD_CLUSTER
181 tristate "Cluster Support for MD (EXPERIMENTAL)"
182 depends on BLK_DEV_MD
183 depends on DLM
184 default n
185 ---help---
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.
189
190 This brings the redundancy (and uptime) of RAID levels across the
191 nodes of the cluster.
192
193 If unsure, say N.
194
195source "drivers/md/bcache/Kconfig"
196
197config BLK_DEV_DM_BUILTIN
198 bool
199
200config BLK_DEV_DM
201 tristate "Device mapper support"
202 select BLK_DEV_DM_BUILTIN
203 ---help---
204 Device-mapper is a low level volume manager. It works by allowing
205 people to specify mappings for ranges of logical sectors. Various
206 mapping types are available, in addition people may write their own
207 modules containing custom mappings if they wish.
208
209 Higher level volume managers such as LVM2 use this driver.
210
211 To compile this as a module, choose M here: the module will be
212 called dm-mod.
213
214 If unsure, say N.
215
216config DM_MQ_DEFAULT
217 bool "request-based DM: use blk-mq I/O path by default"
218 depends on BLK_DEV_DM
219 ---help---
220 This option enables the blk-mq based I/O path for request-based
221 DM devices by default. With the option the dm_mod.use_blk_mq
222 module/boot option defaults to Y, without it to N, but it can
223 still be overriden either way.
224
225 If unsure say N.
226
227config DM_DEBUG
228 bool "Device mapper debugging support"
229 depends on BLK_DEV_DM
230 ---help---
231 Enable this for messages that may help debug device-mapper problems.
232
233 If unsure, say N.
234
235config DM_BUFIO
236 tristate
237 depends on BLK_DEV_DM
238 ---help---
239 This interface allows you to do buffered I/O on a device and acts
240 as a cache, holding recently-read blocks in memory and performing
241 delayed writes.
242
243config DM_DEBUG_BLOCK_STACK_TRACING
244 bool "Keep stack trace of persistent data block lock holders"
245 depends on STACKTRACE_SUPPORT && DM_BUFIO
246 select STACKTRACE
247 ---help---
248 Enable this for messages that may help debug problems with the
249 block manager locking used by thin provisioning and caching.
250
251 If unsure, say N.
252
253config DM_BIO_PRISON
254 tristate
255 depends on BLK_DEV_DM
256 ---help---
257 Some bio locking schemes used by other device-mapper targets
258 including thin provisioning.
259
260source "drivers/md/persistent-data/Kconfig"
261
262config DM_CRYPT
263 tristate "Crypt target support"
264 depends on BLK_DEV_DM
265 select CRYPTO
266 select CRYPTO_CBC
267 ---help---
268 This device-mapper target allows you to create a device that
269 transparently encrypts the data on it. You'll need to activate
270 the ciphers you're going to use in the cryptoapi configuration.
271
272 For further information on dm-crypt and userspace tools see:
273 <https://gitlab.com/cryptsetup/cryptsetup/wikis/DMCrypt>
274
275 To compile this code as a module, choose M here: the module will
276 be called dm-crypt.
277
278 If unsure, say N.
279
280config DM_SNAPSHOT
281 tristate "Snapshot target"
282 depends on BLK_DEV_DM
283 select DM_BUFIO
284 ---help---
285 Allow volume managers to take writable snapshots of a device.
286
287config DM_THIN_PROVISIONING
288 tristate "Thin provisioning target"
289 depends on BLK_DEV_DM
290 select DM_PERSISTENT_DATA
291 select DM_BIO_PRISON
292 ---help---
293 Provides thin provisioning and snapshots that share a data store.
294
295config DM_CACHE
296 tristate "Cache target (EXPERIMENTAL)"
297 depends on BLK_DEV_DM
298 default n
299 select DM_PERSISTENT_DATA
300 select DM_BIO_PRISON
301 ---help---
302 dm-cache attempts to improve performance of a block device by
303 moving frequently used data to a smaller, higher performance
304 device. Different 'policy' plugins can be used to change the
305 algorithms used to select which blocks are promoted, demoted,
306 cleaned etc. It supports writeback and writethrough modes.
307
308config DM_CACHE_SMQ
309 tristate "Stochastic MQ Cache Policy (EXPERIMENTAL)"
310 depends on DM_CACHE
311 default y
312 ---help---
313 A cache policy that uses a multiqueue ordered by recent hits
314 to select which blocks should be promoted and demoted.
315 This is meant to be a general purpose policy. It prioritises
316 reads over writes. This SMQ policy (vs MQ) offers the promise
317 of less memory utilization, improved performance and increased
318 adaptability in the face of changing workloads.
319
320config DM_CACHE_CLEANER
321 tristate "Cleaner Cache Policy (EXPERIMENTAL)"
322 depends on DM_CACHE
323 default y
324 ---help---
325 A simple cache policy that writes back all data to the
326 origin. Used when decommissioning a dm-cache.
327
328config DM_ERA
329 tristate "Era target (EXPERIMENTAL)"
330 depends on BLK_DEV_DM
331 default n
332 select DM_PERSISTENT_DATA
333 select DM_BIO_PRISON
334 ---help---
335 dm-era tracks which parts of a block device are written to
336 over time. Useful for maintaining cache coherency when using
337 vendor snapshots.
338
339config DM_MIRROR
340 tristate "Mirror target"
341 depends on BLK_DEV_DM
342 ---help---
343 Allow volume managers to mirror logical volumes, also
344 needed for live data migration tools such as 'pvmove'.
345
346config DM_LOG_USERSPACE
347 tristate "Mirror userspace logging"
348 depends on DM_MIRROR && NET
349 select CONNECTOR
350 ---help---
351 The userspace logging module provides a mechanism for
352 relaying the dm-dirty-log API to userspace. Log designs
353 which are more suited to userspace implementation (e.g.
354 shared storage logs) or experimental logs can be implemented
355 by leveraging this framework.
356
357config DM_RAID
358 tristate "RAID 1/4/5/6/10 target"
359 depends on BLK_DEV_DM
360 select MD_RAID1
361 select MD_RAID10
362 select MD_RAID456
363 select BLK_DEV_MD
364 ---help---
365 A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings
366
367 A RAID-5 set of N drives with a capacity of C MB per drive provides
368 the capacity of C * (N - 1) MB, and protects against a failure
369 of a single drive. For a given sector (row) number, (N - 1) drives
370 contain data sectors, and one drive contains the parity protection.
371 For a RAID-4 set, the parity blocks are present on a single drive,
372 while a RAID-5 set distributes the parity across the drives in one
373 of the available parity distribution methods.
374
375 A RAID-6 set of N drives with a capacity of C MB per drive
376 provides the capacity of C * (N - 2) MB, and protects
377 against a failure of any two drives. For a given sector
378 (row) number, (N - 2) drives contain data sectors, and two
379 drives contains two independent redundancy syndromes. Like
380 RAID-5, RAID-6 distributes the syndromes across the drives
381 in one of the available parity distribution methods.
382
383config DM_ZERO
384 tristate "Zero target"
385 depends on BLK_DEV_DM
386 ---help---
387 A target that discards writes, and returns all zeroes for
388 reads. Useful in some recovery situations.
389
390config DM_MULTIPATH
391 tristate "Multipath target"
392 depends on BLK_DEV_DM
393 # nasty syntax but means make DM_MULTIPATH independent
394 # of SCSI_DH if the latter isn't defined but if
395 # it is, DM_MULTIPATH must depend on it. We get a build
396 # error if SCSI_DH=m and DM_MULTIPATH=y
397 depends on !SCSI_DH || SCSI
398 ---help---
399 Allow volume managers to support multipath hardware.
400
401config DM_MULTIPATH_QL
402 tristate "I/O Path Selector based on the number of in-flight I/Os"
403 depends on DM_MULTIPATH
404 ---help---
405 This path selector is a dynamic load balancer which selects
406 the path with the least number of in-flight I/Os.
407
408 If unsure, say N.
409
410config DM_MULTIPATH_ST
411 tristate "I/O Path Selector based on the service time"
412 depends on DM_MULTIPATH
413 ---help---
414 This path selector is a dynamic load balancer which selects
415 the path expected to complete the incoming I/O in the shortest
416 time.
417
418 If unsure, say N.
419
420config DM_DELAY
421 tristate "I/O delaying target"
422 depends on BLK_DEV_DM
423 ---help---
424 A target that delays reads and/or writes and can send
425 them to different devices. Useful for testing.
426
427 If unsure, say N.
428
429config DM_UEVENT
430 bool "DM uevents"
431 depends on BLK_DEV_DM
432 ---help---
433 Generate udev events for DM events.
434
435config DM_FLAKEY
436 tristate "Flakey target"
437 depends on BLK_DEV_DM
438 ---help---
439 A target that intermittently fails I/O for debugging purposes.
440
441config DM_VERITY
442 tristate "Verity target support"
443 depends on BLK_DEV_DM
444 select CRYPTO
445 select CRYPTO_HASH
446 select DM_BUFIO
447 ---help---
448 This device-mapper target creates a read-only device that
449 transparently validates the data on one underlying device against
450 a pre-generated tree of cryptographic checksums stored on a second
451 device.
452
453 You'll need to activate the digests you're going to use in the
454 cryptoapi configuration.
455
456 To compile this code as a module, choose M here: the module will
457 be called dm-verity.
458
459 If unsure, say N.
460
461config DM_VERITY_FEC
462 bool "Verity forward error correction support"
463 depends on DM_VERITY
464 select REED_SOLOMON
465 select REED_SOLOMON_DEC8
466 ---help---
467 Add forward error correction support to dm-verity. This option
468 makes it possible to use pre-generated error correction data to
469 recover from corrupted blocks.
470
471 If unsure, say N.
472
473config DM_SWITCH
474 tristate "Switch target support (EXPERIMENTAL)"
475 depends on BLK_DEV_DM
476 ---help---
477 This device-mapper target creates a device that supports an arbitrary
478 mapping of fixed-size regions of I/O across a fixed set of paths.
479 The path used for any specific region can be switched dynamically
480 by sending the target a message.
481
482 To compile this code as a module, choose M here: the module will
483 be called dm-switch.
484
485 If unsure, say N.
486
487config DM_LOG_WRITES
488 tristate "Log writes target support"
489 depends on BLK_DEV_DM
490 ---help---
491 This device-mapper target takes two devices, one device to use
492 normally, one to log all write operations done to the first device.
493 This is for use by file system developers wishing to verify that
494 their fs is writing a consistent file system at all times by allowing
495 them to replay the log in a variety of ways and to check the
496 contents.
497
498 To compile this code as a module, choose M here: the module will
499 be called dm-log-writes.
500
501 If unsure, say N.
502
503endif # MD