2.4.19 Enclosure Management; Raid Levels; Summary Of Raid Levels - Lenovo ThinkServer RD240 Software User's Manual

2.4.19 Enclosure Management

2.5

RAID Levels

2.5.1

Summary of RAID Levels

2-16
Enclosure management is the intelligent monitoring of the disk
subsystem by software and/or hardware. The disk subsystem can be part
of the host computer or can reside in an external disk enclosure.
Enclosure management helps you stay informed of events in the disk
subsystem, such as a drive or power supply failure. Enclosure
management increases the fault tolerance of the disk subsystem.
The RAID controller supports RAID levels 0, 00, 1, 5, 6, 10, 50, and 60.
The supported RAID levels are summarized in the following section.
In addition, it supports independent drives (configured as RAID 0 and
RAID 00.) The following sections describe the RAID levels in detail.
RAID 0 uses striping to provide high data throughput, especially for large
files in an environment that does not require fault tolerance.
RAID 1 uses mirroring so that data written to one drive is simultaneously
written to another drive. This is good for small databases or other
applications that require small capacity but complete data redundancy.
RAID 5 uses disk striping and parity data across all drives (distributed
parity) to provide high data throughput, especially for small random
access.
RAID 6 uses distributed parity, with two independent parity blocks per
stripe, and disk striping. A RAID 6 virtual drive can survive the loss of
two drives without losing data. A RAID 6 drive group, which requires a
minimum of three drives, is similar to a RAID 5 drive group. Blocks of
data and parity information are written across all drives. The parity
information is used to recover the data if one or two drives fail in the drive
group.
A RAID 00 drive group is a spanned drive group that creates a striped
set from a series of RAID 0 drive groups.
Introduction to RAID