User guide

Dual RAID Module User's Guide - Rev. A03 StorCase Technology, Inc.
Appendix B - Array Basics 137
Table B-1: RAID Level Comparisons
Comparing RAID Levels
Table B-1 illustrates the differences between the various RAID levels.
RAID
Level
Minimum #
of Drives
Description Pros Cons
RAID 0
2 Data striping
without
redundancy
Highest
performance
No data protection - if
one drive fails, all data
is lost
RAID 1 2 Disk mirroring Very high
performance and
data protection
Good write
performance
High redundancy
costs - twice the
storage capacity is
required
RAID 3 3 Block-level data
striping with
dedicated parity
drive
Excellent
performance for
large, sequential
data requests
Poorly suited for
transaction-oriented
network applications
Single parity drives do
not support multiple,
simultaneous read/write
requests
RAID 4
(Not
widely
used)
3 Data striping
supports multiple
simultaneous read
requests
Write requests suffer
from same single parity
drive bottlenecks as
RAID 3
RAID 5 offers equal
data protection and
better performance at
same cost
Block-level data
striping with
dedicated parity
drive
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