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 "Multipath I/O support"
112 depends on BLK_DEV_MD
114 Multipath-IO is the ability of certain devices to address the same
115 physical disk over multiple 'IO paths'. The code ensures that such
116 paths can be defined and handled at runtime, and ensures that a
117 transparent failover to the backup path(s) happens if a IO errors
118 arrives on the primary path.
123 tristate "Device mapper support"
126 Device-mapper is a low level volume manager. It works by allowing
127 people to specify mappings for ranges of logical sectors. Various
128 mapping types are available, in addition people may write their own
129 modules containing custom mappings if they wish.
131 Higher level volume managers such as LVM2 use this driver.
133 To compile this as a module, choose M here: the module will be
139 bool "ioctl interface version 4"
140 depends on BLK_DEV_DM
142 Recent tools use a new version of the ioctl interface, only
143 select this option if you intend using such tools.