Appendix, High availability, Global hot spares – DATOptic ARC-1680 Series User Manual

Page 170

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APPENDIX

170

tion 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 Hot Spares

A Global Hot Spare is an unused online available drive, which is

ready for replacing the failure disk. The Global Hot Spare is one

of the most important features that SAS RAID controllers provide

to deliver a high degree of fault-tolerance. A Global Hot Spare

is a spare physical drive that has been marked as a global hot

spare and therefore is not a member of any RAID set. If a disk

drive used in a volume set fails, then the Global Hot Spare will

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