Dell 6 series User Manual page 151

Redundant Virtual Disk
A redundant virtual disk is one which has redundant data on physical disks in
the disk group that can be used to rebuild a failed physical disk. A virtual disk
can use disk striping across the physical disks, disk mirroring or parity to provide
redundancy. This offers protection in case of a physical disk failure.
Replace Member
The procedure used to copy data from a source physical disk of a virtual disk to a
target physical disk that is not a part of the virtual disk. The Replace Member
operation is often used to create or restore a specific physical configuration for an
array (for example, a specific arrangement of array members on the device I/O
buses). The Replace Member operation can be run automatically or manually.
Typically, a physical disk fails or is expected to fail, and the data is rebuilt on a hot
spare. The failed physical disk is replaced with a new disk. Then the data is copied
from the hot spare to the new physical disk, and the hot spare reverts from a
rebuild drive to its original hot spare status. The Replace Member operation runs
as a background activity, and the virtual disk is still available online to the host.
Replacement Disk
A physical disk replacing a failed member disk in a virtual disk.
Replacement Unit
A component or collection of components in a system or subsystem that is
always replaced as a unit when any part of the collection fails. Typical
replacement units in a disk subsystem include disks, controller logic boards,
power supplies and cables.
Revertible Hot Spare
When you use the Replace Member procedure, after data is copied from a
hot spare to a new physical disk, the hot spare reverts from a rebuild drive to
its original hot spare status.
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Glossary