Root/drivers/md/Kconfig

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 MD_MULTIPATH
158    tristate "Multipath I/O support"
159    depends on BLK_DEV_MD
160    help
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.
165
166      If unsure, say N.
167
168config MD_FAULTY
169    tristate "Faulty test module for MD"
170    depends on BLK_DEV_MD
171    help
172      The "faulty" module allows for a block device that occasionally returns
173      read or write errors. It is useful for testing.
174
175      In unsure, say N.
176
177config BLK_DEV_DM
178    tristate "Device mapper support"
179    ---help---
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.
184
185      Higher level volume managers such as LVM2 use this driver.
186
187      To compile this as a module, choose M here: the module will be
188      called dm-mod.
189
190      If unsure, say N.
191
192config DM_DEBUG
193    boolean "Device mapper debugging support"
194    depends on BLK_DEV_DM
195    ---help---
196      Enable this for messages that may help debug device-mapper problems.
197
198      If unsure, say N.
199
200config DM_BUFIO
201       tristate
202       depends on BLK_DEV_DM
203       ---help---
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
206     delayed writes.
207
208config DM_BIO_PRISON
209       tristate
210       depends on BLK_DEV_DM
211       ---help---
212     Some bio locking schemes used by other device-mapper targets
213     including thin provisioning.
214
215source "drivers/md/persistent-data/Kconfig"
216
217config DM_CRYPT
218    tristate "Crypt target support"
219    depends on BLK_DEV_DM
220    select CRYPTO
221    select CRYPTO_CBC
222    ---help---
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.
226
227      Information on how to use dm-crypt can be found on
228
229      <http://www.saout.de/misc/dm-crypt/>
230
231      To compile this code as a module, choose M here: the module will
232      be called dm-crypt.
233
234      If unsure, say N.
235
236config DM_SNAPSHOT
237       tristate "Snapshot target"
238       depends on BLK_DEV_DM
239       ---help---
240         Allow volume managers to take writable snapshots of a device.
241
242config DM_THIN_PROVISIONING
243       tristate "Thin provisioning target"
244       depends on BLK_DEV_DM
245       select DM_PERSISTENT_DATA
246       select DM_BIO_PRISON
247       ---help---
248         Provides thin provisioning and snapshots that share a data store.
249
250config DM_DEBUG_BLOCK_STACK_TRACING
251    boolean "Keep stack trace of thin provisioning block lock holders"
252    depends on STACKTRACE_SUPPORT && DM_THIN_PROVISIONING
253    select STACKTRACE
254    ---help---
255      Enable this for messages that may help debug problems with the
256      block manager locking used by thin provisioning.
257
258      If unsure, say N.
259
260config DM_CACHE
261       tristate "Cache target (EXPERIMENTAL)"
262       depends on BLK_DEV_DM
263       default n
264       select DM_PERSISTENT_DATA
265       select DM_BIO_PRISON
266       ---help---
267         dm-cache attempts to improve performance of a block device by
268         moving frequently used data to a smaller, higher performance
269         device. Different 'policy' plugins can be used to change the
270         algorithms used to select which blocks are promoted, demoted,
271         cleaned etc. It supports writeback and writethrough modes.
272
273config DM_CACHE_MQ
274       tristate "MQ Cache Policy (EXPERIMENTAL)"
275       depends on DM_CACHE
276       default y
277       ---help---
278         A cache policy that uses a multiqueue ordered by recent hit
279         count to select which blocks should be promoted and demoted.
280         This is meant to be a general purpose policy. It prioritises
281         reads over writes.
282
283config DM_CACHE_CLEANER
284       tristate "Cleaner Cache Policy (EXPERIMENTAL)"
285       depends on DM_CACHE
286       default y
287       ---help---
288         A simple cache policy that writes back all data to the
289         origin. Used when decommissioning a dm-cache.
290
291config DM_MIRROR
292       tristate "Mirror target"
293       depends on BLK_DEV_DM
294       ---help---
295         Allow volume managers to mirror logical volumes, also
296         needed for live data migration tools such as 'pvmove'.
297
298config DM_RAID
299       tristate "RAID 1/4/5/6/10 target"
300       depends on BLK_DEV_DM
301       select MD_RAID1
302       select MD_RAID10
303       select MD_RAID456
304       select BLK_DEV_MD
305       ---help---
306     A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings
307
308     A RAID-5 set of N drives with a capacity of C MB per drive provides
309     the capacity of C * (N - 1) MB, and protects against a failure
310     of a single drive. For a given sector (row) number, (N - 1) drives
311     contain data sectors, and one drive contains the parity protection.
312     For a RAID-4 set, the parity blocks are present on a single drive,
313     while a RAID-5 set distributes the parity across the drives in one
314     of the available parity distribution methods.
315
316     A RAID-6 set of N drives with a capacity of C MB per drive
317     provides the capacity of C * (N - 2) MB, and protects
318     against a failure of any two drives. For a given sector
319     (row) number, (N - 2) drives contain data sectors, and two
320     drives contains two independent redundancy syndromes. Like
321     RAID-5, RAID-6 distributes the syndromes across the drives
322     in one of the available parity distribution methods.
323
324config DM_LOG_USERSPACE
325    tristate "Mirror userspace logging"
326    depends on DM_MIRROR && NET
327    select CONNECTOR
328    ---help---
329      The userspace logging module provides a mechanism for
330      relaying the dm-dirty-log API to userspace. Log designs
331      which are more suited to userspace implementation (e.g.
332      shared storage logs) or experimental logs can be implemented
333      by leveraging this framework.
334
335config DM_ZERO
336    tristate "Zero target"
337    depends on BLK_DEV_DM
338    ---help---
339      A target that discards writes, and returns all zeroes for
340      reads. Useful in some recovery situations.
341
342config DM_MULTIPATH
343    tristate "Multipath target"
344    depends on BLK_DEV_DM
345    # nasty syntax but means make DM_MULTIPATH independent
346    # of SCSI_DH if the latter isn't defined but if
347    # it is, DM_MULTIPATH must depend on it. We get a build
348    # error if SCSI_DH=m and DM_MULTIPATH=y
349    depends on SCSI_DH || !SCSI_DH
350    ---help---
351      Allow volume managers to support multipath hardware.
352
353config DM_MULTIPATH_QL
354    tristate "I/O Path Selector based on the number of in-flight I/Os"
355    depends on DM_MULTIPATH
356    ---help---
357      This path selector is a dynamic load balancer which selects
358      the path with the least number of in-flight I/Os.
359
360      If unsure, say N.
361
362config DM_MULTIPATH_ST
363    tristate "I/O Path Selector based on the service time"
364    depends on DM_MULTIPATH
365    ---help---
366      This path selector is a dynamic load balancer which selects
367      the path expected to complete the incoming I/O in the shortest
368      time.
369
370      If unsure, say N.
371
372config DM_DELAY
373    tristate "I/O delaying target"
374    depends on BLK_DEV_DM
375    ---help---
376    A target that delays reads and/or writes and can send
377    them to different devices. Useful for testing.
378
379    If unsure, say N.
380
381config DM_UEVENT
382    bool "DM uevents"
383    depends on BLK_DEV_DM
384    ---help---
385    Generate udev events for DM events.
386
387config DM_FLAKEY
388       tristate "Flakey target"
389       depends on BLK_DEV_DM
390       ---help---
391         A target that intermittently fails I/O for debugging purposes.
392
393config DM_VERITY
394    tristate "Verity target support"
395    depends on BLK_DEV_DM
396    select CRYPTO
397    select CRYPTO_HASH
398    select DM_BUFIO
399    ---help---
400      This device-mapper target creates a read-only device that
401      transparently validates the data on one underlying device against
402      a pre-generated tree of cryptographic checksums stored on a second
403      device.
404
405      You'll need to activate the digests you're going to use in the
406      cryptoapi configuration.
407
408      To compile this code as a module, choose M here: the module will
409      be called dm-verity.
410
411      If unsure, say N.
412
413endif # MD
414

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