HP A7143A RAID160 SA Controller Support Guide

Glossary 165
Glossary
ACU (Array Configuration Utility) A
configuration utility useful both for novices
and for more experienced RAID users.
ADU (Array Diagnostic Utility) A
diagnostic tool that collects comprehensive
information about the array controllers in a
system and lists any problems detected.
ARM (Auto-Reliability Monitoring) Also
known as surface analysis. A fault
management feature whereby hard drives
are scanned for bad sectors, and data in the
faulty sectors is remapped onto good sectors.
Parity data consistency is also checked for
drives in RAID 5 or RAID ADG
configurations. Operates as a background
process.
array A set of physical drives configured
into one or more logical drives. Arrayed
drives have significant performance and
data protection advantages over non-arrayed
drives.
array accelerator A component of some
Smart Array controllers that dramatically
improves disk read and write performance
by providing a buffer. Data integrity is
protected by a backup battery and ECC
memory.
array capacity expansion See capacity
expansion.
Automatic Data Recovery Also known as
rebuild. A process that automatically
reconstructs data from a failed drive and
writes it onto a replacement drive. Rebuild
time depends on several factors, but at least
15 minutes should be allowed per gigabyte.
cache A high-speed memory component,
used to store data temporarily for rapid
access.
capacity expansion Abbreviation for array
capacity expansion. The addition of physical
drives to a pre-existing drive array, and
redistribution of existing logical drives and
data over the enlarged array. The size of the
logical drives does not change.
capacity extension Abbreviation for
logical drive capacity extension. The
enlargement of a logical drive without
disruption of data. There must be free space
on the array before extension can occur. If
necessary, create free space by deleting a
logical drive or by carrying out a capacity
expansion. Capacity extension can be carried
out online with some operating systems.
CISS Acronym for “Command Interface for
SCSI-3 Support Specification”.
controller duplexing A type of fault
tolerance that requires two Smart Array
controllers. Each controller has its own set of
drives, and the drive sets have identical
data. When one controller fails, the other
automatically takes over the servicing of
requests. controller duplexing is available
only for some operating systems.
data guarding See RAID.
data striping Writing data to logical drives
in interleaved chunks (by byte or by sector).
This technique improves system
performance.
drive mirroring See RAID.
ECC (error correction and checking)
memory A type of memory that checks and
corrects single-bit or multi-bit memory
errors (depending on configuration) without
causing the server to halt or corrupt data.