ATTO Technology FastStream SC 5700 - Manual (Page 67)

xx
RAID Level 0: striping, no redundancy
RAID Level 0 (striping) is based on the fact that
increased performance can be achieved by
simultaneously accessing data across multiple drives,
increasing data transfer rates while reducing average
access time by overlapping drive seeks. Drives are
accessed alternately, as if stacked one on top of the other. RAID Level 0 provides no data protection. If one
drive fails, all data within that stripe set is lost.
RAID Level 0 is used by applications requiring high
performance for non-critical data.
The ATTO FastStream supports 2 to 16 drives per
RAID Level 0 group.
RAID Level 1: mirroring (duplicate drives)
RAID Level 1 ensures the security of data by writing
the exact same data simultaneously to two different
drives. 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. This application is used for critical data which cannot
be at risk to be lost or corrupted due to the failure of a
single drive.
The ATTO FastStream supports an even number of 2
to16 drives per RAID Level 1 group.
RAID Level 1 plus additional mirroring
RAID Level 1 with multiple mirrors uses at least 3
drives with the same data on each drive. This
application offers the highest fault-tolerance with good performance, especially for small database
applications.
Stripe 2
Stripe 3
Data 12
Data 8
Data 4
Data 11
Data 7
Data 3
Data 10
Data 6
Data 2
Data 9
Data 5
Data 1
Stripe 1
Disk 1 Disk 2 Disk 3 Disk 4
Data 3
Data 2
Data 1
Data 3
Data 2
Data 1
Disk 1 Disk 2
Data 3
Data 2
Data 1
Data 3
Data 2
Data 1
Data 3
Data 2
Data 1
Disk 1 Disk 2 Disk 3
RAID Level 1: additional mirror