107
APPENDIX
In the illustration, volume 1 can be assigned a RAID level 5 of
operation while volume 0 might be assigned a RAID level 1E of
operation. Alternatively, the free space can be used to create vol-
ume 2, which could then be set to use RAID level 5.
Ease of Use Features
•
Foreground Availability/Background Initialization
RAID 0 and RAID 1 volume sets can be used immediately af-
ter creation because they do not create parity data. However,
RAID 3, 5, 6, 30, 50 or 60 volume sets must be initialized to
generate parity information. In Background Initialization, the
initialization proceeds as a background task, and the volume
set is fully accessible for system reads and writes. The oper-
ating system can instantly access the newly created arrays
without requiring a reboot and without waiting for initialization
to complete. Furthermore, the volume set is protected against
disk failures while initialing. If using Foreground Initialization,
the initialization process must be completed before the vol
-
ume set is ready for system accesses.
• Online
Array Roaming
RAID controllers store RAID configuration information on the
disk drives. The controller therefore protects the configuration
settings in the event of controller failure. Online array roam-
ing allows the administrators the ability to move a complete
RAID set to another system without losing RAID configuration
information or data on that RAID set. Therefore, if a server
fails, the RAID set disk drives can be moved to another server
with an Areca RAID controllers and the disks can be inserted
in any order.
•
Online Capacity Expansion
Online Capacity Expansion makes it possible to add one or
more physical drives to a volume set without interrupting
server operation, eliminating the need to backup and restore
after reconfiguration of the RAID set. When disks are added
to a RAID set, unused capacity is added to the end of the
