2.4.14 Disk Rebuilds - Lenovo ThinkServer RD240 Software User's Manual

2.4.14 Disk Rebuilds

•
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 an 18 GB drive, the hot spare
must be 18 GB or larger.
When a drive in a RAID drive group fails, you can rebuild the drive by
recreating the data that was stored on the drive before it failed. The RAID
controller recreates the data using the data stored on the other drives in
the drive group. Rebuilding can be done 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 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 to a hot spare begins. If the system
goes down during a rebuild, the RAID controller automatically restarts
the rebuild after the system reboots.
Note: When the rebuild to a hot spare begins, the failed drive is
often removed from the virtual drive before management
applications detect the failed drive. When this occurs, the
events 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 begins to a hot
spare.
Note: If a source drive fails during a rebuild to a hot spare, the
rebuild 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 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.
Components and Features 2-13