Overland Storage REO 9000 - Manual (Page 15)

Important Concepts to Understand W 15
Setup Guide
Redundant Array of Independent Disks (RAID)
RAID provides convenient, low-cost, reliable storage by saving data on
more than one disk drive simultaneously. If one disk drive in a RAID 5
configuration becomes unavailable, the others continue to work in a
degraded state, thus avoiding downtime for users.
Note: Because RAID 5 is designed for data protection, you might see
performance degradation when compared to JBOD operations.
RAID allows you to group the individual disk drives on the REO
Appliance into logical disk drives of different sizes. You can configure
your REO Appliance to create two physical RAID volumes by selecting
either of the following RAID options:
„ RAID 0. This configuration uses striping, which provides enhanced
performance and volume-level capacity. It divides the data into blocks
and writes each block to a separate disk drive, which improves
performance by dispersing the input and output load. RAID 0 does not
provide data redundancy.
„ RAID 5. This configuration uses striping and distributed parity,
which provides a balance between performance and availability. In
addition to dividing the data into blocks as described for RAID 0, the
parity information is also striped across the disks. If one of the disk
drives fails, you can use the parity information to rebuild the lost data.
In addition to using either of the preceding RAID configurations, you can
also take advantage of logical volume management (LVM) and create
logical volumes from the data pool.
Server 4
Management
browser
interface (console)
Server 3 Server 2 Server 1
GbE or 10/100
LAN
10/100
Management
Backup server
Tape sub-system
SCSI
Server 8 Server 7 Server 6 Server 5
GbE or 10/100
GbE or 10/100
GbE or 10/100
GbE or 10/100
GbE or 10/100
GbE or 10/100
GbE or 10/100
GbE or 10/100
Backup server
Tape sub-system
SCSI
REO