Instruction manual

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ATTO Technology Inc. FastStream SC 5700 Installation and Operation Manual
Appendix A Designing RAID groups
The ATTO FastStream SC 5700 provides instant hardware data protection and intelligence to existing
Fibre Channel storage independent of the storage type.
CAUTIONCAUTION
Selecting RAID configuration causes all
previous storage data on the drive to be
erased. Make sure all of your information is
backed up before setting up RAID groups.
RAID improves data accessibility and
reliability during normal operations, but
you still need a good backup strategy for
long-term protection of your data.
The ATTO FastStream SC 5700 allows RAID
functionality. In general, the process begins with
individual drives also called block devices.
Note
If a drive has corrupt or outdated configuration
data, that drive cannot be assigned to any
RAID group. Ensure all drives to be assigned
to RAID groups are configured properly. Refer
to
Initialize and verify drives on page 20 and
Update RAID configuration data on page 28.
A RAID group is a virtual, independent single
drive whose data is written to physical drives
according to a RAID algorithm. The ATTO
FastStream SC 5700 supports JBOD, RAID Level
0, RAID Level 1, DVRAID, RAID Level 10 and
RAID Level 5.
JBOD (Just a Bunch of Disks)
JBOD (Just a Bunch of Disks) configuration
allows many individual drives to be available for
normal storage operations with no special data
protection.
Using the ATTO FastStream SC 5700 allows you
to concatenate several individual drives into one
large drive.
A JBOD drive can be constructed as a special case
of a RAID group. When multiple physical drives
are assigned to a JBOD RAID group, their storage
areas appear as a single spanned area of storage.
The ATTO FastStream SC 5700 supports 1 to 32
drives per JBOD-configured RAID group.
Exhibit A-1 JBOD: Just a Bunch of Disks: no
redundancy; each disk is treated independently
RAID Level 0
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. RAID Level 0 groups provide data
that is striped across several drives. 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.
The ATTO FastStream SC 5700 supports 2 to 32
drives per RAID Level 0 group.
RAID Level 0 is used by applications requiring
high performance for non-critical data.
Exhibit A-2 RAID Level 0, no redundancy
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.
JBOD
Disk 0Disk 1Disk 2
D0 D4 D8
D1 D5 D9
D2 D6 D10
D3 D7 D11
RAID Level 0
Stripe Disk 0 Disk 1 Disk 2 Disk 3 Disk 4 Disk 5
0 D0D1D2D3D4D5
1 D6D7D8D9D10D11
2 D12 D13 D14 D15 D16 D17
3 D18 D19 D20 D21 D22 D23