17.4.  RAID Support in the Installer

The Anaconda installer will automatically detect any hardware and firmware RAID sets on a system, making them available for installation. Anaconda also supports software RAID using mdraid, and can recognize existing mdraid sets.
Anaconda provides utilities for creating RAID sets during installation; however, these utilities only allow partitions (as opposed to entire disks) to be members of new sets. To use an entire disk for a set, simply create a partition on it spanning the entire disk, and use that partition as the RAID set member.
When the root file system uses a RAID set, Anaconda will add special kernel command-line options to the bootloader configuration telling the initrd which RAID set(s) to activate before searching for the root file system.
For instructions on configuring RAID during installation, refer to the Red Hat Enterprise Linux 7 Installation Guide.