Raid 5 Drive Group With Six Drives; Raid 5 Overview - Lenovo ThinkServer RD240 Software User's Manual

Segment 1 Segment 2
Segment 7 Segment 8
Segment 13 Segment 14
Segment 19 Segment 20
Segment 25
Parity (21-25)
Segment 26
Parity (26–30)
Note: Parity is distributed across all drives in the drive group.
2-20
RAID 5 addresses the bottleneck issue for random I/O operations.
Because each drive contains both data and parity, numerous writes can
take place concurrently.
Table 2.7 provides an overview of RAID 5.
example of a RAID 5 drive group.
Table 2.7

RAID 5 Overview

Uses
Strong Points
Weak Points
Drives
Figure 2.7

RAID 5 Drive Group with Six Drives

Segment 3
Segment 9
Segment 15
Parity (16-20)
Segment 21
Segment 27
Introduction to RAID
Provides high data throughput, especially for large files.
Use RAID 5 for transaction processing applications
because each drive can read and write independently.
If a drive fails, the RAID controller uses the parity drive
to recreate all missing information. Use also for office
automation and online customer service that requires
fault tolerance. Use for any application that has high
read request rates but low write request rates.
Provides data redundancy, high read rates, and good
performance in most environments. Provides
redundancy with lowest loss of capacity.
Not well-suited to tasks requiring lot of writes. Suffers
more impact if no cache is used (clustering). Drive
performance will be reduced if a drive is being rebuilt.
Environments with few processes do not perform as
well because the RAID overhead is not offset by the
performance gains in handling simultaneous processes.
3 to 32
Segment 4
Segment 10
Parity (11–15)
Segment 16
Segment 22
Segment 28
Figure 2.7 provides a graphic
Segment 5 Parity (1-5)
Parity (6-10) Segment 6
Segment 12
Segment 11
Segment 17 Segment 18
Segment 23 Segment 24
Segment 29 Segment 30