Setting Up RAID ArraysSetting Up the ftServer System 5-9Device files are created for the first 128 RAID arrays. Use the mknod command (seemknod(1)) to create additional device files as needed. The number is the minor devicenumber, and it is also used in the name.The smaller numbers are used by the installer, so it is convenient to add new RAIDarrays above 10. When RAID arrays are intended to be moved between systems, tryto pick numbers that are unique among all of the systems.The /etc/mdadm.conf file, which describes all of the RAID arrays for the system, iscreated during installation. This file contains one line for each RAID array. Whencreating a new RAID array, it is convenient to copy an existing line and modify it to suityour needs. Here is a typical line:ARRAY /dev/md2 super-minor=2You can create, start, and stop the RAID arrays. You can manage RAID-1 arrays byadding and removing mirrors.The following sections discuss working with RAID arrays. This includes configuringRAID arrays, administration, and tools.N O T ETo ensure fault-tolerant operation of your system, only usethe mdadm command to create RAID arrays.Creating a RAID-1 ArrayThe example in this discussion uses the disk pair sdb and sde. The RAID array is called/dev/md20 and consists of sdb1 and sde1.To create a RAID-1 array1. Select a pair of same-sized disks and insert them into two corresponding slots indifferent CPU-I/O enclosures. This example uses the middle slot (sdb) of the upperCPU-I/O enclosure, and the middle slot (sde) of the lower enclosure.2. When the disks have spun up, partition them for the desired RAID array (see‘‘Managing Partitions’’ on page 5-4). You can mark the partitions with code 83.
