xref: /openbmc/linux/drivers/md/Kconfig (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1#
2# Block device driver configuration
3#
4
5menu "Multi-device support (RAID and LVM)"
6
7config MD
8	bool "Multiple devices driver support (RAID and LVM)"
9	help
10	  Support multiple physical spindles through a single logical device.
11	  Required for RAID and logical volume management.
12
13config BLK_DEV_MD
14	tristate "RAID support"
15	depends on MD
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_LINEAR
34	tristate "Linear (append) mode"
35	depends on BLK_DEV_MD
36	---help---
37	  If you say Y here, then your multiple devices driver will be able to
38	  use the so-called linear mode, i.e. it will combine the hard disk
39	  partitions by simply appending one to the other.
40
41	  To compile this as a module, choose M here: the module
42	  will be called linear.
43
44	  If unsure, say Y.
45
46config MD_RAID0
47	tristate "RAID-0 (striping) mode"
48	depends on BLK_DEV_MD
49	---help---
50	  If you say Y here, then your multiple devices driver will be able to
51	  use the so-called raid0 mode, i.e. it will combine the hard disk
52	  partitions into one logical device in such a fashion as to fill them
53	  up evenly, one chunk here and one chunk there. This will increase
54	  the throughput rate if the partitions reside on distinct disks.
55
56	  Information about Software RAID on Linux is contained in the
57	  Software-RAID mini-HOWTO, available from
58	  <http://www.tldp.org/docs.html#howto>. There you will also
59	  learn where to get the supporting user space utilities raidtools.
60
61	  To compile this as a module, choose M here: the module
62	  will be called raid0.
63
64	  If unsure, say Y.
65
66config MD_RAID1
67	tristate "RAID-1 (mirroring) mode"
68	depends on BLK_DEV_MD
69	---help---
70	  A RAID-1 set consists of several disk drives which are exact copies
71	  of each other.  In the event of a mirror failure, the RAID driver
72	  will continue to use the operational mirrors in the set, providing
73	  an error free MD (multiple device) to the higher levels of the
74	  kernel.  In a set with N drives, the available space is the capacity
75	  of a single drive, and the set protects against a failure of (N - 1)
76	  drives.
77
78	  Information about Software RAID on Linux is contained in the
79	  Software-RAID mini-HOWTO, available from
80	  <http://www.tldp.org/docs.html#howto>.  There you will also
81	  learn where to get the supporting user space utilities raidtools.
82
83	  If you want to use such a RAID-1 set, say Y.  To compile this code
84	  as a module, choose M here: the module will be called raid1.
85
86	  If unsure, say Y.
87
88config MD_RAID10
89	tristate "RAID-10 (mirrored striping) mode (EXPERIMENTAL)"
90	depends on BLK_DEV_MD && EXPERIMENTAL
91	---help---
92	  RAID-10 provides a combination of striping (RAID-0) and
93	  mirroring (RAID-1) with easier configuration and more flexable
94	  layout.
95	  Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to
96	  be the same size (or at least, only as much as the smallest device
97	  will be used).
98	  RAID-10 provides a variety of layouts that provide different levels
99	  of redundancy and performance.
100
101	  RAID-10 requires mdadm-1.7.0 or later, available at:
102
103	  ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/
104
105	  If unsure, say Y.
106
107config MD_RAID5
108	tristate "RAID-4/RAID-5 mode"
109	depends on BLK_DEV_MD
110	---help---
111	  A RAID-5 set of N drives with a capacity of C MB per drive provides
112	  the capacity of C * (N - 1) MB, and protects against a failure
113	  of a single drive. For a given sector (row) number, (N - 1) drives
114	  contain data sectors, and one drive contains the parity protection.
115	  For a RAID-4 set, the parity blocks are present on a single drive,
116	  while a RAID-5 set distributes the parity across the drives in one
117	  of the available parity distribution methods.
118
119	  Information about Software RAID on Linux is contained in the
120	  Software-RAID mini-HOWTO, available from
121	  <http://www.tldp.org/docs.html#howto>. There you will also
122	  learn where to get the supporting user space utilities raidtools.
123
124	  If you want to use such a RAID-4/RAID-5 set, say Y.  To
125	  compile this code as a module, choose M here: the module
126	  will be called raid5.
127
128	  If unsure, say Y.
129
130config MD_RAID6
131	tristate "RAID-6 mode"
132	depends on BLK_DEV_MD
133	---help---
134	  A RAID-6 set of N drives with a capacity of C MB per drive
135	  provides the capacity of C * (N - 2) MB, and protects
136	  against a failure of any two drives. For a given sector
137	  (row) number, (N - 2) drives contain data sectors, and two
138	  drives contains two independent redundancy syndromes.  Like
139	  RAID-5, RAID-6 distributes the syndromes across the drives
140	  in one of the available parity distribution methods.
141
142	  RAID-6 requires mdadm-1.5.0 or later, available at:
143
144	  ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/
145
146	  If you want to use such a RAID-6 set, say Y.  To compile
147	  this code as a module, choose M here: the module will be
148	  called raid6.
149
150	  If unsure, say Y.
151
152config MD_MULTIPATH
153	tristate "Multipath I/O support"
154	depends on BLK_DEV_MD
155	help
156	  Multipath-IO is the ability of certain devices to address the same
157	  physical disk over multiple 'IO paths'. The code ensures that such
158	  paths can be defined and handled at runtime, and ensures that a
159	  transparent failover to the backup path(s) happens if a IO errors
160	  arrives on the primary path.
161
162	  If unsure, say N.
163
164config MD_FAULTY
165	tristate "Faulty test module for MD"
166	depends on BLK_DEV_MD
167	help
168	  The "faulty" module allows for a block device that occasionally returns
169	  read or write errors.  It is useful for testing.
170
171	  In unsure, say N.
172
173config BLK_DEV_DM
174	tristate "Device mapper support"
175	depends on MD
176	---help---
177	  Device-mapper is a low level volume manager.  It works by allowing
178	  people to specify mappings for ranges of logical sectors.  Various
179	  mapping types are available, in addition people may write their own
180	  modules containing custom mappings if they wish.
181
182	  Higher level volume managers such as LVM2 use this driver.
183
184	  To compile this as a module, choose M here: the module will be
185	  called dm-mod.
186
187	  If unsure, say N.
188
189config DM_CRYPT
190	tristate "Crypt target support"
191	depends on BLK_DEV_DM && EXPERIMENTAL
192	select CRYPTO
193	---help---
194	  This device-mapper target allows you to create a device that
195	  transparently encrypts the data on it. You'll need to activate
196	  the ciphers you're going to use in the cryptoapi configuration.
197
198	  Information on how to use dm-crypt can be found on
199
200	  <http://www.saout.de/misc/dm-crypt/>
201
202	  To compile this code as a module, choose M here: the module will
203	  be called dm-crypt.
204
205	  If unsure, say N.
206
207config DM_SNAPSHOT
208       tristate "Snapshot target (EXPERIMENTAL)"
209       depends on BLK_DEV_DM && EXPERIMENTAL
210       ---help---
211         Allow volume managers to take writeable snapshots of a device.
212
213config DM_MIRROR
214       tristate "Mirror target (EXPERIMENTAL)"
215       depends on BLK_DEV_DM && EXPERIMENTAL
216       ---help---
217         Allow volume managers to mirror logical volumes, also
218         needed for live data migration tools such as 'pvmove'.
219
220config DM_ZERO
221	tristate "Zero target (EXPERIMENTAL)"
222	depends on BLK_DEV_DM && EXPERIMENTAL
223	---help---
224	  A target that discards writes, and returns all zeroes for
225	  reads.  Useful in some recovery situations.
226
227config DM_MULTIPATH
228	tristate "Multipath target (EXPERIMENTAL)"
229	depends on BLK_DEV_DM && EXPERIMENTAL
230	---help---
231	  Allow volume managers to support multipath hardware.
232
233config DM_MULTIPATH_EMC
234	tristate "EMC CX/AX multipath support (EXPERIMENTAL)"
235	depends on DM_MULTIPATH && BLK_DEV_DM && EXPERIMENTAL
236	---help---
237	  Multipath support for EMC CX/AX series hardware.
238
239endmenu
240
241