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Altos RAIDWatch User Guide
C.3 RAID 0
RAID 0 implements block striping where data is broken into logical blocks and striped across several
drives. Although called RAID 0, this is not a true implementation of RAID because there is no facility
for redundancy. In the event of a disk failure, data is lost.
In block striping, the total disk capacity is equivalent to the sum of the capacities of all SCSI drives
in the array. This combination of drives appears to the system as a single logical drive.
RAID 0 provides the highest performance without redundancy. It is fast because data can be
simultaneously transferred to/from multiple disks. Furthermore, read/writes to different drives can
be processed concurrently.
C.4 RAID 1
RAID 1 implements disk mirroring where a copy of the same data is recorded onto two sets of
striped drives. By keeping two copies of data on separate disks or arrays, data is protected against
a disk failure. If, at any time, a disk on either side fails, the good disks can provide all of the data
needed, thus preventing downtime.
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2 GB Hard drive
3 GB Hard drive
1 GB Hard drive
2 GB Hard drive
2 + 3 + 1 + 2 = 8 GB Logical Drive
Block 1
Block 2
Block 1
Block 3
Block 3
Block 4
Block 5
Block 5
Block 7
Block 6
Block 7
Block 8
Block 2
Block 4
Block 6
Block 8
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