RadiSys ATCA-5400 RTM, Справочник

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3 CONFIGURING A REDUNDANT DISK ARRAY
This chapter explains the RTM’s support for RAID (redundant array of inexpensive disks) and
how to configure a RAID from the available hard disk drives. Hard disk drive arrays can be
configured in the SAS BIOS, which is the BIOS for the SAS/SATA controller. Some hard disk
drives must be connected to the RTM with cables before you can include them in an array.
Supported RAID configurations
The RTM’s SAS/SATA controller supports these RAID levels and configurations:

RAID 1 integrated mirroring (IM) , which provides redundancy. Two hard disk drives (a
primary and secondary) must be identified to be used as exact copies. Up to two hot spare
hard disk drives can be included in case one of the copied hard disk drives fails. In case of
failure, the contents of the remaining good hard disk drive can be copied to a hot spare,
which also gets a copy of all new data. The available hard disk drive capacity is the same as
the smallest hard disk drive or spare in the array.

RAID 1 integrated mirroring enhanced (IME) , which provides striping and one copy of
each stripe for redundancy. At least 3 hard disk drives must be used, with a maximum of 8
copies. Up to two hot spare hard disk drives can be included in case one of the participating
hard disk drives fails. The available hard disk drive capacity is the smallest disk capacity in
the array multiplied by the number of hard disk drives in the array, and then divided by two.
This is due to the mirrored stripes used in the IME array.

RAID 0 integrated striping (IS) , which improves performance. At least 3 hard disk drives
must be identified to participate, with a maximum of 10 hard disk drives. The available hard
disk drive capacity is the capacity of the smallest hard disk drive in the array multiplied by
the number of hard disk drives in the array.
The SAS/SATA controller supports multiple arrays at once, including arrays of different types, as
long as the number of available hard disk drives is sufficient to support the arrays. For additional
information on the supported RAID options, see the
Integrated RAID for SAS User’s Guide from
LSI Logic Corporation.