HP StorageWorks XP Performance Advisor Software v4.6 Install Guide (T1789-96096, July 2010)

Glossary
ACP Array Control Processor.
ACP handles the transfer of data between the cache and the physical drives held
in the DKUs. ACPs work in pairs, providing a total of eight SCSI buses. Each
SCSI bus associated with one ACP is paired with a SCSI bus on the other ACP
pair element. In the event of an ACP failure, the redundant ACP takes control.
Both ACPs work together by sharing the load. On XP models, such as the
XP10000, this function is handled by the disk adapter on the MIX board.
ACP was used on XP disk arrays before the advent of the XP24000 type arrays.
With the introduction of XP24000, DKA replaced ACP.
XP Continuous
Access
The HP StorageWorks XP Continuous Access is a software providing remote
replication between XP disk arrays and is used for disaster recovery. XP
Continuous Access is referred to as XP Continuous Access in official HP
documents.
Cache A Cache is a high speed memory that is used to speed up the I/O transaction
time. All reads and writes to the XP disk arrays are sent to the cache. The data
is buffered in the cache until it is transferred to the physical disks or from the
physical disks (with slower data throughput) is complete. The benefit of cache
memory is that it speeds the IO/s 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. In the event of power loss, the battery
power maintains the contents of cache for a specified time period.
XP Continuous
Access Journal
The HP StorageWorks XP Continuous Access Journal is an asynchronous mirroring
program similar to the XP Continuous Access Async Software, except that the
transactions to be written to the secondary XP Disk Array are maintained in a
disk-based journal file. This provides better performance for secondary XP Disk
Array systems that are not highly available or that may be subject to bandwidth
contention from other applications.
CHA Channel Adapter.
CHA provides an interface between an XP Disk Array and the external host
system. Occasionally, this term is used synonymously with the term channel host
interface processor (CHIP).
CHIP Client-Host Interface Processor.
CHIP was used on XP disk arrays before the advent of the XP24000 type arrays.
With the introduction of XP24000, CHIP replaced CHA. However, CHIP appears
in documents written for array types prior to XP24000.
CHP Channel Processor.
The CHP are the micro processors (MP)s located on the channel adapter (CHA).
Synonymously used with CHIP.
CLPR Cache Logical Partition.
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