HP Netserver L Server series - Manual (Page 155)

Appendix B Glossary
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Dual-Active (Duplex) Mode
This is a method of interconnecting multiple RAID controllers that share a
common set of drives. In addition to increasing overall performance, this method
allows a surviving controller to take over resources of a failed controller. This
"failover" process is transparent to the host.
Duplex Mode
See "Dual-Active (Duplex) Mode."
Error Table
See "Bad Block Table (or Bad Data Table)."
Hot Replacement of Disks (“Hot Swap”)
The design of RAID controllers allows for the replacement of failed hard disk
drives without interruption of system service. In the event of a drive failure on a
properly configured system (where the data redundancy features of the controller
are used), system service continues without interruption. A message is generated
by the system to alert the system operator.
When a replacement drive becomes available, the system operator can remove the
failed disk drive, install a new disk drive, and instruct the controller to "rebuild"
the data on the new drive, all without interrupting system operations.
Once the rebuild is complete, the controller will be brought back into a fault
tolerant state.
IBBU
See "Intelligent Battery Backup Unit."
Intelligent Battery Backup Unit
The Intelligent Battery Backup Unit (IBBU) is an add-on module that provides
power to a compatible RAID Controller cache memory in the event of a power
failure. The battery backup module monitors the write back cache on the
controller, and provides power to the cache if it contains data not yet written to the
drives when power is lost.
LUN
See "Logical Unit Number (LUN)."
LUN Mapping
RAID Controller LUN Mapping allows logical drives (or system drives) to be
made available or unavailable on one or more host ports. The mapping is
performed by assigning Logical Unit Numbers (LUNs) to logical drives. The LUN