Glossary - HP StorageWorks XP10000 - Disk Array Manual

Glossary

ACP
AL
AL-PA
allocation
array group
BC
C-Track
Continuous Access
cache
channel adapter
(CHA)
channel host
interface processor
(CHIP)
Array control processor. On some HP XP models, such as the HP XP12000, the
ACP handles the passing of data between the cache and the physical drives.
On other HP XP models, such as the HP XP10000 disk array, this function is
handled by the disk adapter on the MIX board.
Arbitrated loop.
Arbitrated loop physical address.
The ratio of allocated storage capacity versus total capacity as a percentage.
"Allocated storage" refers to those LDEVs that have paths assigned to them. The
allocated storage capacity is the sum of the storage of these LDEVs. Total capacity
refers to the sum of the capacity of all LDEVs on the disk array.
A group of 4 or 8 physical hard disk drives (HDDs) installed in an XP disk array
and assigned a common RAID level. RAID1 array groups consist of 4 (2D+2D)
or 8 HDDs (4D+4D). RAID5 array groups include a parity disk but also consist
of 4 (3D+1P) or 8 HDDs (7D+1P). All RAID6 array groups are made up of 8
HDDs (6D+2P).
HP StorageWorks XP Business Copy Software enables you to maintain up to
nine internal copies of logical volumes on the disk array.
The HP StorageWorks XP Continuous Track software program, which detects
internal hardware component problems on a disk array and automatically reports
them to the HP STC.
HP StorageWorks XP Continuous Access Software enables you to replicate data
stored on a local disk array to a remote disk array.
Very high speed memory that is used to speed I/O transaction time. All reads
and writes to the HP XP array family are sent to the cache. The data is buffered
there until the transfer to/from physical disks (with slower data throughput) is
complete.
The benefit of cache memory is that it speeds I/O throughput to the application.
The larger the cache size, the greater the amount of data buffering that can occur
and the greater throughput to the applications.
XP arrays support a range of cache memory. In the event of power loss, battery
power holds up the contents of cache for up to 36 hours.
The channel adapter (CHA) provides the interface between the disk array and
the external host system. Occasionally this term is used synonymously with the
term channel host interface processor (CHIP).
Synonymous with the term channel adapter (CHA).
XP10000 Disk Array Site Preparation Guide 51