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Selecting a raid level – LSI MegaRAID Express 500 User Manual

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MegaRAID Express 500 Hardware Guide

18

Selecting a RAID Level

Level

Description and

Use

Pros

Cons

Maximum

Physical

Drives

Fault

Tolerant

0

Data divided in
blocks and
distributed
sequentially (pure
striping). Use for
non-critical data
that requires high
performance.

High data
throughput
for large
files

No fault
tolerance. All
data lost if
any drive
fails.

One to 15

No

1

Data duplicated on
another disk
(mirroring). Use
for read-intensive
fault-tolerant
systems.

100% data
redundancy

Doubles disk
space.
Reduced
performance
during
rebuilds.

2

Yes

3

Disk striping with a
dedicated parity
drive. Use for non-
interactive apps
that process large
files sequentially.

Achieves
data
redundancy
at low cost

Performance
not as good as
RAID 1

Three to 15

Yes

5

Disk striping and
parity data across
all drives. Use for
high read volume
but low write
volume, such as
transaction
processing.

Achieves
data
redundancy
at low cost

Performance
not as good as
RAID 1

Three to 15

Yes

10

Data striping and
mirrored drives.

High data
transfers,
complete
redundancy

More
complicated

Four to 14
(must be a

multiple of

two)

Yes

30

Disk striping with a
dedicated parity
drive.

High data
transfers,
redundancy

More
complicated

Six to15

Yes

50

Disk striping and
parity data across
all drives.

High data
transfers,
redundancy

More
complicated

Six to 15

Yes

Note:

The maximum number of physical drives supported by the Express 500 controller is 15.