ATTO Technology FastStream VT 5300 Installation And Operation Manual page 39

RAID Level 1
RAID Level 1 ensures the security of data by
writing the exact same data simultaneously to two
or more different drives. This application is for
users with critical data which cannot be lost or
corrupted due to the failure of a single drive.
With RAID Level 1, the host sees what it believes
to be a single physical drive of a specific size: it
does not know about the mirrored pair.
The ATTO FastStream VT manages where data is
written and read, allowing one drive to fail
without the host knowing it has failed. RAID
Level 1 is used in applications containing mission
critical data. The ATTO FastStream VT supports
an even number of 2 to 32 drives per RAID Level
1 group.
Exhibit A-4 RAID Level 1: Data is written to two or
more drives simultaneously.
RAID Level 1
Stripe Disk 0 Disk 1 Disk 2 Disk 3 Disk 4 Disk 5
0 D0 D0
1 D1 D1
2 D2 D2
3 D3 D3
RAID Level 10
RAID Level 10 increases data transfer rates while
ensuring security by writing the exact same data
simultaneously to two or more different drives.
RAID Level 10 is used in applications requiring
high performance and redundancy, combining the
attributes of RAID Levels 1 and 0.
D4 D4 D8 D8
D5 D5 D9 D9
D6 D6 D10 D10
D7 D7 D11 D11
The ATTO FastStream VT supports an even
number of 4 to 32 drives per RAID Level 10
group.
Exhibit A-5 RAID Level 10 with mirroring and
spanning; redundancy is shown in shaded blocks.
RAID Level 10
Stripe Disk 0 Disk 1 Disk 2 Disk 3 Disk 4 Disk 5
0 D0 D0
1 D3 D3
2 D6 D6
3 D9 D9
RAID Level 5
RAID Level 5 increases reliability while using
fewer drives than mirroring by employing parity
redundancy. Distributed parity on multiple drives
allows you to rebuild a failed drive from the
remaining good drives. The ATTO FastStream
VT operates in degraded mode if a drive fails.
The ATTO FastStream VT supports 3 to 16 drives
per RAID Level 5 group.
Exhibit A-6 RAID Level 5 with parity blocks shaded.
RAID Level 5
Stripe Disk 0 Disk 1 Disk 2 Disk 3 Disk 4 Disk 5
0 D0 D1
1 D6 D7
2 D12 D13
3 D18 D19 P15-19
4 D24 P20-24
5 P25-29 D25
D1 D1 D2 D2
D4 D4 D5 D5
D7 D7 D8 D8
D10 D10 D11 D11
D2 D3 D4 P0-4
D8 D9 P5-9 D5
D14 P10-14 D10 D11
D15 D16 D17
D20 D21 D22 D23
D26 D27 D28 D29
Appendix
vi