Vivotek NR9682-v2 64-Channel NVR (No HDD) - Manual (Page 46)

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46 - User's Manual
Hot spare drives can be located on any RAID channel. Standby hot spares (not being used in
RAID drive group) are polled every 60 seconds at a minimum, and their status made available
in the drive group management software. RAID controllers offer the ability to rebuild with a disk
that is in a system but not initially set to be a hot spare.
Observe the following parameters when using hot spares:
• Hot spares are used only in drive groups with redundancy: RAID levels 1, 5, 6, 10, 50, and
60.
• A hot spare connected to a specific RAID controller can be used to rebuild a drive that is
connected only to the same controller.
• You must assign the hot spare to one or more drives through the controller BIOS or use drive
group management software to place it in the hot spare pool.
• A hot spare must have free space equal to or greater than the drive it replaces. For example,
to replace a 500-GB drive, the hot spare must be 500-GB or larger.
Disk Rebuilds
When a drive in a RAID drive group fails, you can rebuild the drive by re-creating the data that
was stored on the drive before it failed. The RAID controller re-creates the data using the data
stored on the other drives in the drive group. Rebuilding can be performed only in drive groups
with data redundancy, which includes RAID 1, 5, 6, 10, 50, and 60 drive groups.
The RAID controller uses hot spares to rebuild failed drives automatically and transparently,
at user-defined rebuild rates. If a hot spare is available, the Rebuild operation can start
automatically when a drive fails. If a hot spare is not available, the failed drive must be replaced
with a new drive so that the data on the failed drive can be rebuilt.
The failed drive is removed from the virtual drive and marked ready awaiting removal when the
Rebuild operation to a hot spare begins. If the system goes down during a Rebuild operation,
the RAID controller automatically resumes the rebuild after the system reboots.
NOTE :
When the Rebuild operation to a hot spare begins, the failed drive is often removed from
the virtual drive b efo re management applications detect the failed drive. When this removal
occurs, the event logs show the drive rebuilding to the hot spare without showing the failed
drive. The formerly failed drive will be marked as ready after a Rebuild operation begins to a
hot spare. If a source drive fails during a rebuild to a hot spare, the Rebuild operation fails,
and the failed source drive is marked as offline. In addition, the rebuilding hot spare drive
is changed back to a hot spare. After a Rebuild operation fails because of a source drive
failure, the dedicated hot spare is still dedicated and assigned to the correct drive group, and
the global hot spare is still global.
An automatic drive Rebuild operation will not start if you replace a drive during a RAID-level
migration. The Rebuild operation must be started manually after the expansion or migration
procedure is complete. (RAID-level migration changes a virtual drive from one RAID level to
another.)