Integrated HP NetRAID Controller Config. Guide

Glossary
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Virtual Sizing: This setting, when enabled for a logical drive, causes the
controller to report the logical drive size larger than the actual physical capacity.
The "virtual" space allows for online capacity expansion.
Write Policy: When the processor writes to disk, the data is first written to the
cache on the assumption that the processor will probably read it again soon. The
two Write policies for HP NetRAID are:
• Write Back: In a write-back cache, data is written to disk only when it is
forced out of the cache. Write-back requires the cache to initiate a write to
disk of the flushed entry, followed (for a processor read) by a main
memory read. Write-back is efficient because an entry may be written
many times in the cache without a disk access.
• Write Through: In a write-through cache, data is written to disk at the
same time as it is cached. Write-through is simpler than write-back
because an entry that is to be replaced can be overwritten in the cache, as
it will already have been copied to disk.