B Glossary - HP D5970A - NetServer - LCII Installation And User Manual

B Glossary

Active/Active Mode
See "Dual-Active (Duplex) Mode."
BBU
See "Battery Backup Unit."
Bad Block Table (or Bad Data Table)
There are two bad-block tables that the controller automatically maintains. The
Rebuild Bad Block Table stores information on bad blocks encountered during a
rebuild or consistency check process. The Write-Back Bad Block Table stores
information on all irrecoverable write-back errors that occur. FCArray Assistant
provides an Error Table in which you can see Bad Block Data and Request Sense
Data.
Battery Backup Unit
A Battery Backup Unit is an add-on module that provides power to the disk array
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.
Cache
Controller memory used to speed up data transfer to and from a disk.
Cache Flush
Refers to an operation where all unwritten blocks in a Write-Back Cache are
written to the target disk. This operation is necessary before powering down the
system.
Cache Line Size
The Cache Line Size function, available in Controller Options or Manual
Configuration, is set in conjunction with stripe size and represents the size of the
data "chunk" that will be read or written at one time. The cache line size should be
based on the stripe size you selected.
Channel
Refers to one bus on a disk array controller. Each controller provides at least one
channel, with additional channels provided as optional upgrades.
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