NEC N8403-019, User Manual

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Chapter 2 RAID
This chapter describes the RAID features that the disk array controller supports.
1. Overview of RAID
1-1 What is RAID (Redundant Array of Inexpensive Disks)?
RAID is an abbreviation for "Redundant Array of Inexpensive Disks." RAID technology allows more than one
HDD to be handled collectively.
RAID configures multiple HDD
‟s as a single array (disk group) to operate the HDD‟s more effectively. This
can provide higher performance than a single, large capacity HDD.
This disk array controller has a feature to divide a single disk group into several logical drives. The host
computer recognizes these virtual disks as if they were a single HDD. The host computer accesses more
than one HDD when configuring a disk group in parallel.
Some RAID levels can recover data from remaining data and parity by using a rebuild feature if an error
occurs on a single HDD. This can provide high reliability for the system.
1-2 RAID Levels
The disk array controller supports the following RAID levels: RAID 0 and RAID 1. The number of HDD
‟s
required to create a disk group varies depending on the RAID level as shown in the table below:
RAID level
Number of required
HDD’s
Min. Max.
RAID 0 1 2
RAID 1 2 2
Tips
For details of the RAID levels, see "2. RAID Levels" described later in this
chapter.