Mylex eXtremeRAID 1100, Installation Manual

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775013 G-1
Glossary
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 is set in conjunction with stripe size and
represents the size of the data “chunk” that will be read or written at one
time. Under RAID EzAssist, the cache line size (also known as “segment
size”) should be based on the stripe size you selected. The default cache line
size for Mylex eXtremeRAID controllers is 8K.
Channel
Refers to one SCSI bus on a disk array controller. Each disk array controller
provides at least one channel.
Consistency Check
Refers to a process where the integrity of redundant data is verified. For
example, a consistency check of a mirrored drive will make sure that the data
on both drives of the mirrored pair is exactly the same. For RAID Level 3 or
RAID Level 5, a consistency check makes sure that all parity data is correct.
Disk Failure Detection
The controller automatically detects SCSI disk failures. A monitoring
process running on the controller checks, among other things, elapsed time
on all commands issued to disks. A time-out causes the disk to be “reset”
and the command to be retried. If the command times out again, the disk