Raid 50 Overview - Lenovo ThinkServer RD240 Software User's Manual

50 is best implemented on two RAID 5 drive groups with data striped
across both drive groups.
RAID 50 breaks up data into smaller blocks and then stripes the blocks
of data to each RAID 5 disk set. RAID 5 breaks up data into smaller
blocks, calculates parity by performing an exclusive-or on the blocks and
then writes the blocks of data and parity to each drive in the drive group.
The size of each block is determined by the stripe size parameter, which
is set during the creation of the RAID set.
RAID level 50 can support up to eight spans and tolerate up to eight
drive failures, though less than total drive capacity is available. Though
multiple drive failures can be tolerated, only one drive failure can be
tolerated in each RAID 5 level drive group.
Table 2.11
Table 2.11
Uses
Strong Points
Weak Points
Drives
Figure 2.11 RAID 50 Level Virtual Drive
Segment 1
RAID 50
Segment 6
(Segment 9,10)
RAID Levels
provides an overview of RAID 50.

RAID 50 Overview

Appropriate when used with data that requires high
reliability, high request rates, high data transfer, and
medium to large capacity.
Provides high data throughput, data redundancy, and
very good performance.
Requires 2 to 8 times as many parity drives as RAID 5.
Eight spans of RAID 5 drive groups containing 3-32
drives each (limited by the maximum number of devices
supported by the controller)
Segment 2 (Segment 1,2)
Segment 5
(Segment 5,6)
Segment 10
Segment 9
RAID 5
Segment 3 Segment 4
Segment 8 (Segment 7,8)
(Segment 11,12)
Segment 11 Segment 12
RAID 5
RAID 0
(Segment 3,4)
Segment 7
2-25