DATOptic RM12-S6.TB - Rackmount - Manual (Page 77)

APPENDIX
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from migrating state to (migrating+degraded) state. When the
migration is completed, the volume set transitions to degraded
mode. If a global hot spare is present, then it further transitions
to rebuilding state.
• Online Volume Expansion
Performing a volume expansion on the controller is the process
of growing only the size of the latest volume. A more flexible op-
tion is for the array to concatenate an additional drive into the
RAID set and then expand the volumes on the fly. This happens
transparently while the volumes are online, but, at the end of
the process, the operating system will detect free space at after
the existing volume.
Windows, NetWare and other advanced operating systems sup-
port volume expansion, which enables you to incorporate the
additional free space within the volume into the operating sys-
tem partition. The operating system partition is extended to
incorporate the free space so it can be used by the operating
system without creating a new operating system partition.
You can use the Diskpart.exe command line utility, included with
Windows Server 2003 or the Windows 2000 Resource Kit, to ex-
tend an existing partition into free space in the dynamic disk.
Third-party software vendors have created utilities that can be
used to repartition disks without data loss. Most of these utilities
work offline. Partition Magic is one such utility.
High Availability
• Global/Local Hot Spares
A hot spare is an unused online available drive, which is ready
for replacing the failure disk. The hot spare is one of the most
important features that RAID controllers provide to deliver a
high degree of fault-tolerance. A hot spare is a spare physical
drive that has been marked as a hot spare and therefore is not
a member of any RAID set. If a disk drive used in a volume set
fails, then the hot spare will automatically take its place and he