2.4.13 Hot Spares; Spanning For Raid 10, Raid 50, And Raid - Lenovo ThinkServer RD240 Software User's Manual

2.4.13 Hot Spares

Table 2.2

Spanning for RAID 10, RAID 50, and RAID 60

Level Description
00 Configure RAID 00 by spanning two contiguous RAID 0 virtual
drives, up to the maximum number of supported devices for the
controller.
10 Configure RAID 10 by spanning two contiguous RAID 1 virtual
drives, up to the maximum number of supported devices for the
controller. RAID 10 supports a maximum of eight spans. You must
use an even number of drives in each RAID virtual drive in the
span. The RAID 1 virtual drives must have the same stripe size.
50 Configure RAID 50 by spanning two contiguous RAID 5 virtual
drives. The RAID 5 virtual drives must have the same stripe size.
60 Configure RAID 60 by spanning two contiguous RAID 6 virtual
drives. The RAID 6 virtual drives must have the same stripe size.
A hot spare is an extra, unused drive that is part of the disk subsystem.
It is usually in standby mode, ready for service if a drive fails. Hot spares
permit you to replace failed drives without system shutdown or user
intervention. MegaRAID SAS RAID controllers can implement automatic
and transparent rebuilds of failed drives using hot spare drives, providing
a high degree of fault tolerance and zero downtime.
Note: When running RAID 0 and RAID 5 virtual drives on the
same set of drives (a sliced configuration), a rebuild to a
hot spare will not occur after a drive failure until the
RAID 0 virtual drive is deleted.
The RAID management software allows you to specify drives as hot
spares. When a hot spare is needed, the RAID controller assigns the hot
spare that has a capacity closest to and at least as great as that of the
failed drive to take the place of the failed drive. The failed drive is
removed from the virtual drive and marked ready awaiting removal once
the rebuild to a hot spare begins. You can make hot spares of the drives
that are not in a RAID virtual drive.
You can use the RAID management software to designate the hot spare
to have enclosure affinity, meaning that if there are drive failures present
on a split backplane configuration, the hot spare will be used first on the
backplane side that it resides in.
Components and Features 2-11