Kernel 2.4
As of version 2.4, software RAID has its own subsection in the
kernel configuration (in previous versions, options were found under
the Block Devices submenu). The Multi-device Support (RAID and LVM)
submenu contains all the configuration options for software RAID. The
first option, CONFIG_MD, is a configuration switch
that reveals options for RAID and Logical Volume Management (LVM).
After selecting CONFIG_MD, choose
CONFIG_BLK_DEV_MD, which allows the kernel to
address multiple physical devices through a single logical device (see
Figure 3-1).
CONFIG_BLK_DEV_MD provides the foundation for the
md driver and needs to be enabled on every system
that uses software RAID, regardless of which RAID level is
implemented.
In order to successfully build a software RAID device, one of the available RAID levels must also be enabled. The following kernel directives enable support for specific RAID levels:
CONFIG_MD_LINEAR CONFIG_MD_RAID0 CONFIG_MD_RAID1 CONFIG_MD_RAID5
CONFIG_MD_LINEAR and
CONFIG_MD_RAID0 enable support for the non-RAID
methods of disk grouping supported by the Linux kernel.
CONFIG_MD_RAID1 provides support for data
redundancy through disk mirroring. Finally,
CONFIG_MD_RAID5 enables support for both RAID-4 and RAID-5 layouts. The choice between using RAID-4 or RAID-5 is made later, when creating an array. If you plan to experiment ...
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