HP XP48 Manuel du propriétaire télécharger pdf (Page 98)

HP SureStore E Disk Array XP512/XP48: Owner’s Guide

Understanding RAID3

RAID3 is not supported on your XP disk array, but it is a preface to

understanding RAID5, which is supported.

RAID3 allows data to be split and distributed on two or more disk drives

using striping. Because two or more disk drives are recording the data

simultaneously, the transfer speed is faster. The multiple disk drives that are

used to store the data are called a parity group. See figure 14 (page 98).

RAID3 stores parity information on a separate drive (called a parity drive).

This improves the safety of your data because the parity information can be

used to recover the data, even if one of the drives in a parity group has

become inoperative or has read errors.

Because RAID3 does not have parallel input/output capability, it must drive

two or more drives at the same time. This causes poor performance in

applications that process small data files often (transaction processing).

RAID3 has good performance when you are using applications that process

large data files in a single run (scientific computations).

Figure 14. RAID3 Disk Array

DATA

A B C D E F

. . .

A2 A3A1

Striping

Parity

Generation

Correction Code

RAID Controller

AP1

BP1

CP1

DP1

1 2 ... 93 94 95 96 97 98 99 100 101 102 103 ... 123 124

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HP XP48 Manuel du propriétaire Page 98