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Hot-Swap Disk Drive Support
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The RAID controller chip includes a protection circuit that supports the replacement of SAS/SATA hard disk
drives without having to shut down or reboot the system. A removable hard drive tray can deliver "hot
swappable" fault-tolerant RAID solutions. This feature provides advanced fault tolerant RAID protection and
"online" drive replacement.
Auto Declare Hot-Spare
•
If a disk drive is brought online into a system operating in degraded mode, the RAID controllers will
automatically declare the new disk as a spare and begin rebuilding the degraded volume. The Auto Declare
Hot-Spare function requires that the smallest drive contained within the volume set in which the failure
occurred.
In the normal status, the newly installed drive will be reconfigured an online free disk. But, the
newly-installed drive is automatically assigned as a hot spare if any hot spare disk was used to rebuild and
without new installed drive replaced it. In this condition, the Auto Declare Hot-Spare status will be
disappeared if the RAID subsystem has since powered off/ on.
The Hot-Swap function can be used to rebuild disk drives in arrays with data redundancy such as RAID level
1, 1E, 3, 5, 6, 10, 30, 50 and 60.
Auto Rebuilding
•
If a hot spare is available, the rebuild starts automatically when a drive fails. The RAID controllers
automatically and transparently rebuild failed drives in the background at user definable rebuild rates.
If a hot spare is not available, the failed disk drive must be replaced with a new disk drive so that the data on
the failed drive can be automatically rebuilt and so that fault tolerance can be maintained.
RAID controllers will automatically restart the system and rebuilding process if the system is shut down or
powered off abnormally during a reconstruction procedure condition.
When a disk is hot swapped, although the system is functionally operational, the system may no longer be
fault tolerant. Fault tolerance will be lost until the removed drive is replaced and the rebuild operation is
completed.
During the automatic rebuild process, system activity will continue as normal, however, the system
performance and fault tolerance will be affected.
Adjustable Rebuild Priority
•
Rebuilding a degraded volume incurs a load on the RAID sub system. The RAID controllers allow the user to
select the rebuild priority to balance volume access and rebuild tasks appropriately. The Background Task
Priority is a relative indication of how much time the controller devotes to a background operation, such as
rebuilding or migrating.
RAID controller allows user to choose the task priority (Ultra Low (5%), Low (20%), Medium (50%), High
(80%)) to balance volume set access and background tasks appropriately. For high array performance,
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