Areca 24/4 Internal/External Port Pcie 3.0 12 Gb/s SAS/SATA Raid Controller 2Gb Cache - Manual (Page 250)

APPENDIX
250
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
data previously located on the failed drive is reconstructed on
the hot spare.
Dedicated hot spare is assigned to serve one specified RAID
set. Global hot spare is assigned to serve all RAID set on the
RAID controller. Dedicated hot spare has higher priority than
the global hot spare. For this feature to work properly, the hot
spare must have at least the same capacity as the drive it re-
places. The host spare function only works with RAID level 1,
1E, 3, 5, 6, 10, 30, 50, or 60 volume set.
The “Create Hot Spare” option gives you the ability to define a
global/dedicated hot spare disk drive. To effectively use the hot
spare feature, you must always maintain at least one drive that
is marked as a global hot spare.
Important:
The hot spare must have at least the same capacity as the
drive it replaces.
• Hot-Swap Disk Drive Support
The RAID controller chip includes a protection circuit that sup-
ports 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 solu-
tions. This feature provides advanced fault tolerant RAID pro-
tection and “online” drive replacement.
• Auto Declare Hot-Spare
If a disk drive is brought online into a system operating in de-
graded mode, the RAID controllers will automatically declare
the new disk as a spare and begin rebuilding the degraded vol-
ume. The Auto Declare Hot-Spare function requires that the
smallest drive contained within the volume set in which the
failure occurred.