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Linux/drivers/md/Kconfig

  1 #
  2 # Block device driver configuration
  3 #
  4 
  5 menuconfig 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 
 13 if MD
 14 
 15 config 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 
 34 config 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 
 48 config 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 
 61 config 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 
 81 config 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 
103 config 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 
122 config MD_RAID456
123         tristate "RAID-4/RAID-5/RAID-6 mode"
124         depends on BLK_DEV_MD
125         select RAID6_PQ
126         select ASYNC_MEMCPY
127         select ASYNC_XOR
128         select ASYNC_PQ
129         select ASYNC_RAID6_RECOV
130         ---help---
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.
138 
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.
146 
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.
151 
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.
155 
156           If unsure, say Y.
157 
158 config MD_MULTIPATH
159         tristate "Multipath I/O support"
160         depends on BLK_DEV_MD
161         help
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.
166 
167           If unsure, say N.
168 
169 config MD_FAULTY
170         tristate "Faulty test module for MD"
171         depends on BLK_DEV_MD
172         help
173           The "faulty" module allows for a block device that occasionally returns
174           read or write errors.  It is useful for testing.
175 
176           In unsure, say N.
177 
178 
179 config MD_CLUSTER
180         tristate "Cluster Support for MD (EXPERIMENTAL)"
181         depends on BLK_DEV_MD
182         depends on DLM
183         default n
184         ---help---
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.
188 
189         This brings the redundancy (and uptime) of RAID levels across the
190         nodes of the cluster.
191 
192         If unsure, say N.
193 
194 source "drivers/md/bcache/Kconfig"
195 
196 config BLK_DEV_DM_BUILTIN
197         bool
198 
199 config BLK_DEV_DM
200         tristate "Device mapper support"
201         select BLK_DEV_DM_BUILTIN
202         ---help---
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.
207 
208           Higher level volume managers such as LVM2 use this driver.
209 
210           To compile this as a module, choose M here: the module will be
211           called dm-mod.
212 
213           If unsure, say N.
214 
215 config DM_MQ_DEFAULT
216         bool "request-based DM: use blk-mq I/O path by default"
217         depends on BLK_DEV_DM
218         ---help---
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.
223 
224           If unsure say N.
225 
226 config DM_DEBUG
227         bool "Device mapper debugging support"
228         depends on BLK_DEV_DM
229         ---help---
230           Enable this for messages that may help debug device-mapper problems.
231 
232           If unsure, say N.
233 
234 config DM_BUFIO
235        tristate
236        depends on BLK_DEV_DM
237        ---help---
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
240          delayed writes.
241 
242 config DM_BIO_PRISON
243        tristate
244        depends on BLK_DEV_DM
245        ---help---
246          Some bio locking schemes used by other device-mapper targets
247          including thin provisioning.
248 
249 source "drivers/md/persistent-data/Kconfig"
250 
251 config DM_CRYPT
252         tristate "Crypt target support"
253         depends on BLK_DEV_DM
254         select CRYPTO
255         select CRYPTO_CBC
256         ---help---
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.
260 
261           For further information on dm-crypt and userspace tools see:
262           <http://code.google.com/p/cryptsetup/wiki/DMCrypt>
263 
264           To compile this code as a module, choose M here: the module will
265           be called dm-crypt.
266 
267           If unsure, say N.
268 
269 config DM_SNAPSHOT
270        tristate "Snapshot target"
271        depends on BLK_DEV_DM
272        select DM_BUFIO
273        ---help---
274          Allow volume managers to take writable snapshots of a device.
275 
276 config DM_THIN_PROVISIONING
277        tristate "Thin provisioning target"
278        depends on BLK_DEV_DM
279        select DM_PERSISTENT_DATA
280        select DM_BIO_PRISON
281        ---help---
282          Provides thin provisioning and snapshots that share a data store.
283 
284 config DM_CACHE
285        tristate "Cache target (EXPERIMENTAL)"
286        depends on BLK_DEV_DM
287        default n
288        select DM_PERSISTENT_DATA
289        select DM_BIO_PRISON
290        ---help---
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.
296 
297 config DM_CACHE_MQ
298        tristate "MQ Cache Policy (EXPERIMENTAL)"
299        depends on DM_CACHE
300        default y
301        ---help---
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
305          reads over writes.
306 
307 config DM_CACHE_CLEANER
308        tristate "Cleaner Cache Policy (EXPERIMENTAL)"
309        depends on DM_CACHE
310        default y
311        ---help---
312          A simple cache policy that writes back all data to the
313          origin.  Used when decommissioning a dm-cache.
314 
315 config DM_ERA
316        tristate "Era target (EXPERIMENTAL)"
317        depends on BLK_DEV_DM
318        default n
319        select DM_PERSISTENT_DATA
320        select DM_BIO_PRISON
321        ---help---
322          dm-era tracks which parts of a block device are written to
323          over time.  Useful for maintaining cache coherency when using
324          vendor snapshots.
325 
326 config DM_MIRROR
327        tristate "Mirror target"
328        depends on BLK_DEV_DM
329        ---help---
330          Allow volume managers to mirror logical volumes, also
331          needed for live data migration tools such as 'pvmove'.
332 
333 config DM_LOG_USERSPACE
334         tristate "Mirror userspace logging"
335         depends on DM_MIRROR && NET
336         select CONNECTOR
337         ---help---
338           The userspace logging module provides a mechanism for
339           relaying the dm-dirty-log API to userspace.  Log designs
340           which are more suited to userspace implementation (e.g.
341           shared storage logs) or experimental logs can be implemented
342           by leveraging this framework.
343 
344 config DM_RAID
345        tristate "RAID 1/4/5/6/10 target"
346        depends on BLK_DEV_DM
347        select MD_RAID1
348        select MD_RAID10
349        select MD_RAID456
350        select BLK_DEV_MD
351        ---help---
352          A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings
353 
354          A RAID-5 set of N drives with a capacity of C MB per drive provides
355          the capacity of C * (N - 1) MB, and protects against a failure
356          of a single drive. For a given sector (row) number, (N - 1) drives
357          contain data sectors, and one drive contains the parity protection.
358          For a RAID-4 set, the parity blocks are present on a single drive,
359          while a RAID-5 set distributes the parity across the drives in one
360          of the available parity distribution methods.
361 
362          A RAID-6 set of N drives with a capacity of C MB per drive
363          provides the capacity of C * (N - 2) MB, and protects
364          against a failure of any two drives. For a given sector
365          (row) number, (N - 2) drives contain data sectors, and two
366          drives contains two independent redundancy syndromes.  Like
367          RAID-5, RAID-6 distributes the syndromes across the drives
368          in one of the available parity distribution methods.
369 
370 config DM_ZERO
371         tristate "Zero target"
372         depends on BLK_DEV_DM
373         ---help---
374           A target that discards writes, and returns all zeroes for
375           reads.  Useful in some recovery situations.
376 
377 config DM_MULTIPATH
378         tristate "Multipath target"
379         depends on BLK_DEV_DM
380         # nasty syntax but means make DM_MULTIPATH independent
381         # of SCSI_DH if the latter isn't defined but if
382         # it is, DM_MULTIPATH must depend on it.  We get a build
383         # error if SCSI_DH=m and DM_MULTIPATH=y
384         depends on SCSI_DH || !SCSI_DH
385         ---help---
386           Allow volume managers to support multipath hardware.
387 
388 config DM_MULTIPATH_QL
389         tristate "I/O Path Selector based on the number of in-flight I/Os"
390         depends on DM_MULTIPATH
391         ---help---
392           This path selector is a dynamic load balancer which selects
393           the path with the least number of in-flight I/Os.
394 
395           If unsure, say N.
396 
397 config DM_MULTIPATH_ST
398         tristate "I/O Path Selector based on the service time"
399         depends on DM_MULTIPATH
400         ---help---
401           This path selector is a dynamic load balancer which selects
402           the path expected to complete the incoming I/O in the shortest
403           time.
404 
405           If unsure, say N.
406 
407 config DM_DELAY
408         tristate "I/O delaying target"
409         depends on BLK_DEV_DM
410         ---help---
411         A target that delays reads and/or writes and can send
412         them to different devices.  Useful for testing.
413 
414         If unsure, say N.
415 
416 config DM_UEVENT
417         bool "DM uevents"
418         depends on BLK_DEV_DM
419         ---help---
420         Generate udev events for DM events.
421 
422 config DM_FLAKEY
423        tristate "Flakey target"
424        depends on BLK_DEV_DM
425        ---help---
426          A target that intermittently fails I/O for debugging purposes.
427 
428 config DM_VERITY
429         tristate "Verity target support"
430         depends on BLK_DEV_DM
431         select CRYPTO
432         select CRYPTO_HASH
433         select DM_BUFIO
434         ---help---
435           This device-mapper target creates a read-only device that
436           transparently validates the data on one underlying device against
437           a pre-generated tree of cryptographic checksums stored on a second
438           device.
439 
440           You'll need to activate the digests you're going to use in the
441           cryptoapi configuration.
442 
443           To compile this code as a module, choose M here: the module will
444           be called dm-verity.
445 
446           If unsure, say N.
447 
448 config DM_SWITCH
449         tristate "Switch target support (EXPERIMENTAL)"
450         depends on BLK_DEV_DM
451         ---help---
452           This device-mapper target creates a device that supports an arbitrary
453           mapping of fixed-size regions of I/O across a fixed set of paths.
454           The path used for any specific region can be switched dynamically
455           by sending the target a message.
456 
457           To compile this code as a module, choose M here: the module will
458           be called dm-switch.
459 
460           If unsure, say N.
461 
462 config DM_LOG_WRITES
463         tristate "Log writes target support"
464         depends on BLK_DEV_DM
465         ---help---
466           This device-mapper target takes two devices, one device to use
467           normally, one to log all write operations done to the first device.
468           This is for use by file system developers wishing to verify that
469           their fs is writing a consitent file system at all times by allowing
470           them to replay the log in a variety of ways and to check the
471           contents.
472 
473           To compile this code as a module, choose M here: the module will
474           be called dm-log-writes.
475 
476           If unsure, say N.
477 
478 endif # MD

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