Sans Digital ER208UT+B, Руководство пользователя

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APPENDIX
147
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, and 6 volume sets must be initialized to generate
parity information. In Background Initialization, the initializa-
tion proceeds as a background task, and the volume set is fully
accessible for system reads and writes. The operating system
can instantly access the newly created arrays without requir-
ing 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 initializa-
tion process must be completed before the volume set is ready
for system accesses.
• Online
Array Roaming
The RAID subsystems store RAID configuration information on
the disk drives. The controller therefore protects the configu -
ration settings in the event of controller failure. Online array
roaming allows the administrators the ability to move a com-
plete RAID set to another system without losing RAID configura -
tion 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 Sans Digital SAS/SATA 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 op-
eration, eliminating the need to backup and restore after recon-
figuration of the RAID set. When disks are added to a RAID set,
unused capacity is added to the end of the RAID set. Then, data