2 # Block device driver configuration
5 menu "Multi-device support (RAID and LVM)"
8 bool "Multiple devices driver support (RAID and LVM)"
10 Support multiple physical spindles through a single logical device.
11 Required for RAID and logical volume management.
14 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 tristate "Linear (append) mode"
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.
41 To compile this as a module, choose M here: the module
42 will be called linear.
47 tristate "RAID-0 (striping) mode"
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.
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.
61 To compile this as a module, choose M here: the module
67 tristate "RAID-1 (mirroring) mode"
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)
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.
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.
89 tristate "RAID-4/RAID-5 mode"
92 A RAID-5 set of N drives with a capacity of C MB per drive provides
93 the capacity of C * (N - 1) MB, and protects against a failure
94 of a single drive. For a given sector (row) number, (N - 1) drives
95 contain data sectors, and one drive contains the parity protection.
96 For a RAID-4 set, the parity blocks are present on a single drive,
97 while a RAID-5 set distributes the parity across the drives in one
98 of the available parity distribution methods.
100 Information about Software RAID on Linux is contained in the
101 Software-RAID mini-HOWTO, available from
102 <http://www.tldp.org/docs.html#howto>. There you will also
103 learn where to get the supporting user space utilities raidtools.
105 If you want to use such a RAID-4/RAID-5 set, say Y. To compile
106 this code as a module, choose M here: the module will be called raid5.
111 tristate "RAID-6 mode (EXPERIMENTAL)"
112 depends on BLK_DEV_MD && EXPERIMENTAL
114 WARNING: RAID-6 is currently highly experimental. If you
115 use it, there is no guarantee whatsoever that it won't
116 destroy your data, eat your disk drives, insult your mother,
117 or re-appoint George W. Bush.
119 A RAID-6 set of N drives with a capacity of C MB per drive
120 provides the capacity of C * (N - 2) MB, and protects
121 against a failure of any two drives. For a given sector
122 (row) number, (N - 2) drives contain data sectors, and two
123 drives contains two independent redundancy syndromes. Like
124 RAID-5, RAID-6 distributes the syndromes across the drives
125 in one of the available parity distribution methods.
127 RAID-6 requires mdadm-1.5.0 or later, available at:
129 ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/
131 If you want to use such a RAID-6 set, say Y. To compile
132 this code as a module, choose M here: the module will be
138 tristate "Multipath I/O support"
139 depends on BLK_DEV_MD
141 Multipath-IO is the ability of certain devices to address the same
142 physical disk over multiple 'IO paths'. The code ensures that such
143 paths can be defined and handled at runtime, and ensures that a
144 transparent failover to the backup path(s) happens if a IO errors
145 arrives on the primary path.
150 tristate "Device mapper support"
153 Device-mapper is a low level volume manager. It works by allowing
154 people to specify mappings for ranges of logical sectors. Various
155 mapping types are available, in addition people may write their own
156 modules containing custom mappings if they wish.
158 Higher level volume managers such as LVM2 use this driver.
160 To compile this as a module, choose M here: the module will be
166 tristate "Crypt target support"
167 depends on BLK_DEV_DM && EXPERIMENTAL
170 This device-mapper target allows you to create a device that
171 transparently encrypts the data on it. You'll need to activate
172 the ciphers you're going to use in the cryptoapi configuration.
174 Information on how to use dm-crypt can be found on
176 http://www.saout.de/misc/dm-crypt/
178 To compile this code as a module, choose M here: the module will