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RAID Management
The subsystem can implement several different levels of RAID technology. RAID levels
supported by the subsystem are shown below.
RAID
Level
Description
Min
Drives
0
Block striping is provide, which yields higher performance than
with individual drives. There is no redundancy.
2
1
Drives are paired and mirrored. All data is 100% duplicated on
an equivalent drive. Fully redundant.
2
3
Data is striped across several physical drives. Parity protection is
used for data redundancy.
3
5
Data is striped across several physical drives. Parity protection is
used for data redundancy.
3
6
Data is striped across several physical drives. Parity protection is
used for data redundancy. Requires N+2 drives to implement
because of two-dimensional parity scheme
4
0 + 1
Combination of RAID levels 0 and 1. This level provides striping
and redundancy through mirroring.
4
30
Combination of RAID levels 0 and 3. This level is best
implemented on two RAID 3 disk arrays with data striped across
both disk arrays.
6
50
RAID 50 provides the features of both RAID 0 and RAID 5. RAID
50 includes both parity and disk striping across multiple drives.
RAID 50 is best implemented on two RAID 5 disk arrays with
data striped across both disk arrays.
6
4.2 SCSI Concepts
Before configuring the subsystem, you must first understand some basic SCSI concepts so
that the subsystem and SCSI devices will function properly.
4.2.1 Multiple SCSI Format Support
The subsystem support the SCSI interface standards listed below. Note that the data bit and
cable length restrictions must be followed.
SCSI Type
Data Bit
Data Rate
Cable Length
SCSI-1
8 Bits
5 MB/Sec
6 m
Fast SCSI
8 Bits
10 MB/Sec
3 m
Fast Wide SCSI
16 Bits
20 MB/Sec
3 m
Ultra SCSI
8 Bits
20 MB/Sec
1.5 m
Ultra Wide SCSI
16 Bits
40 MB/Sec
1.5 m
Ultra 2 SCSI
8 Bits
40 MB/Sec
12 m
