Logic MegaRAID Express User's Guide

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.
2Yes
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.