Adaptec 5325301507 - Snap Server 4400 NAS, Administrator'S Manual

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RAIDs
Chapter 4 Storage Configuration and Expansion 53
Automatic Incorporation of Hot-Swapped Drives
If a RAID (except RAID 0) is running in degraded mode and a raw drive, a non-
GuardianOS drive, or an unassigned GuardianOS-partitioned drive is “hot-
inserted” into a SnapServer, it can be automatically assigned as a local spare and
used to rebuild the degraded RAID. If there are no degraded RAIDs, a hot-inserted
non-GuardianOS or unassigned drive will be automatically configured as a global
hot spare. To enable the automatic incorporation of an unassigned drive, go to the
Storage > RAID Sets
screen and click the
RAID Settings
button.
Background Disk Scan
The background disk scan checks the integrity of RAID data by continuously
scanning the disk drives for errors. Each RAID (except RAID 0) has its own
background disk scan that is set to run when the I/O activity falls to a very low disk
activity. Once the activity rises above the idle threshold , the background scan stops
and waits for the activity to fall to the idle threshold again before resuming. As a
result, there should be minimal to no impact on performance. Once the disk scan
has completed a pass on a given RAID set, it waits a certain period of time before
starting again.
Identifying Hot spares are identified on the Storage > Disks/Units screen using
the following icons:
Each icon will be associated with a disk in the RAID, identifying that
disk as either a local hot spare or a global hot spare.
Interaction When a drive in a RAID fails, the system looks for a hot spare in the
following order:
1
If a local hot spare dedicated to the RAID exists, use the local hot
spare.
2
If no local hot spare is available, and there is a single hot spare of
sufficient capacity, use the global hot spare.
3
If no local hot spare is available, and two global hot spares of
different capacity are available, use the smaller hot spare with
sufficient capacity.
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