Glossary For The Hp Xp24000/Xp20000 Disk Array - HP StorageWorks XP20000/XP24000 - Disk Array Owner's Manual

Glossary for the HP XP24000/XP20000
Disk Array
ACP
AL
AL-PA
allocation
array group
BC
C-Track
cache
channel adapter
(CHA)
channel processor
(CHP)
command device
Array control processor. On some XP models, such as the XP12000, the ACP
handles the passing of data between the cache and the physical drives. On other
XP models, such as the XP10000, 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 four identical unformatted disk drives (HDDs). Array groups are
formatted into parity groups (also called RAID groups).
The HP StorageWorks XP Business Copy software program, which enables you
to maintain up to nine internal copies of logical volumes on the disk array.
The HP StorageWorks XP Continuous Track remote support solution, which detects
internal hardware component problems on a disk array and automatically reports
them to the HP STC (Storage Technology Center). C-Track also enables STC
remote diagnosis of the array. There are both Internet-based and modem-based
C-Track solutions for the XP24000/XP20000 disk arrays.
Very high speed memory that is used to speed I/O transaction time. All reads
and writes to the 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 maintains the contents of cache for a specified time period.
The channel adapter (CHA) provides the interface between the disk array and
the external host system.
The processors located on the channel adapter (CHA). Synonymous with CHIP.
A volume on the disk array that accepts Continuous Access or Business Copy
control operations which are then executed by the disk array.
XP24000/XP20000 Disk Array Owner's Guide 57