Smart Array 5300 Controller User Guide

Drive Arrays and Fault Tolerance

Figure D-4: Two arrays (A1, A2) containing five logical

drives spread over five physical drives

Each logical drive in an array is distributed over all of the physical drives within the

array. A logical drive can also extend over more than one port on the same controller,

but it cannot extend over more than one controller.

Drive failure, although rare, is potentially catastrophic. In Figure D-4, for example,

failure of any physical drive causes all logical drives in the same array to fail, and all

data on the drives is lost.

To protect against data loss due to physical drive failure, logical drives are

configured with fault tolerance. There are several fault-tolerance methods; those

supported by current HP and Compaq branded controllers (and described in the

following section) are:

•

RAID 0—Data Striping only (no fault tolerance)

RAID 1+0—Drive Mirroring

RAID 5—Distributed Data Guarding

RAID ADG—Advanced Data Guarding

D-4 HP Smart Array 5300 Controller User Guide

HP CONFIDENTIAL

Writer: Kimberly Koch File Name: m-appd drive arrays and fault tolerance.doc

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