HP XP Array Manager Software - Manual (Page 12)

1-2 Overview of Hitachi Cache Manager
Hitachi Cache Manager User’s Guide
Hitachi Cache Manager
Cache Manager enables users to perform Cache Residency Manager operations
on Hitachi RAID storage systems from the mainframe host console. Cache
Residency Manager enables users to store specific data in cache memory to
make the data available to the host at front-end access speeds. The disk
drives are not accessed.
For more information about Cache Residency Manager, please see the Hitachi
Cache Residency Manager User’s Guide for the storage system.
Figure 1-1 illustrates some of the differences between Cache Residency
Manager and Cache Manager.
Mainframe HOST System
Cache Manager
Hitachi RAID Storage System
CACHE for DCR
002E 003D
USER.FILE
Remote
Console PC SVP
Cache Residency: Specify
by physical address (CCHH)
Example: specify physical
address “002E-003D”
Cache Manager: Specify by
dataset name, VTOC and
physical address (CCHH)
Example: specify dataset
name “USER>FILE”
Figure 1-1 Specifying Cache by Dataset Name, VTOC and CCHH
The Cache Manager areas (called cache extents) have the following
parameters:
• They are dynamic and can only be added and deleted online.
• Data defined by a continuous CCHH area will be considered as one extent.
A BIND mode area and a PRIO (priority) mode area are considered
different extents (see
Overview of Priority Mode and Bind Mode ). The
number of datasets and the number of resident extents will not necessarily
match (e.g., when a dataset consists of noncontiguous extents).