Disk Arrays - Hitachi Compute Rack CR 210H User Manual

Disk arrays

This section describes the disk array functions.
About disk arrays
The disk array is a technique used as one or more logical units (LU) by connecting
two or more HDDs to each other, which is also referred to as a Redundant Arrays
of Inexpensive Disks (RAID).
The disk array has two main advantages: one is to segment data into some
component and decentralize onto the HDDs in the disk array (data striping) in
order to improve I/O performance higher than a single disk in terms of a disk
array, and the other is to create an array parity for data recovery in order to
prevent data loss in case one of the HDDs in the disk array should fail.
NOTICE
3-2
Even the disk array cannot prevent data loss that is caused by a
non-HDD failure, software overrun or operation errors. Just in case,
back up your system data.
Disk array:

A virtual drive consisting of multiple physical drives, which cannot
be recognized by the OS as it is.
Logical drive:

A logical drive configured in the disk array, which is recognized by
the OS in the same manner as a physical drive.
You can assign capacity larger than 2 TB (2199 GB) for the logical

drive set as disk array but do not assign capacity larger than 2 TB
for the logical drive the OS is installed to. Otherwise the OS cannot
create a partition anymore. Use the RAID management utility or the
RAID BIOS to reconstruct the disk arrays and the logical drives.
System Unit Functions
Hitachi Compute Rack 210H User's Guide