Areca 24/4 Internal/External Port Pcie 3.0 12 Gb/s SAS/SATA Raid Controller 2Gb Cache - Manual (Page 249)

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APPENDIX
of disk failure(s). In the case of disk failure, the volume set
transitions from migrating state to (migrating+degraded)
state. When the migration is completed, the volume set tran-
sitions 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 pro-
cess of growing only the size of the latest volume. A more
flexible option 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 de-
tect free space at after the existing volume.
Windows, NetWare and other advanced operating systems
support volume expansion, which enables you to incorporate
the additional free space within the volume into the operat-
ing system partition. The operating system partition is extend-
ed to incorporate the free space so it can be used by the oper-
ating system without creating a new operating system parti-
tion.
You can use the Diskpart.exe command line utility, included
with Windows Server 2003 or the Windows 2000 Resource Kit,
to extend 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 utili-
ties 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