Hitachi Virtual Storage Platform, User And Reference Manual

Page: 43 / 146

Functional and Operational Characteristics
2–15
Hitachi VSP User and Reference Guide
449 Universal
Replicator
Universal
Replicator for
Mainframe Detecting and monitoring path blockade between
MCU and RCU of Universal Replicator/Universal
Replicator for z/OS
<Functionality>
- Mode 449 on: Detecting and monitoring of path
blockade will NOT be performed.
- Mode 449 off (default *) : Detecting and
monitoring of the path blockade will be performed.
* Newly shipped DKC will have Mode 449 = ON as
default.
Note: The mode status will not be changed by the
microcode exchange.
454 Virtual
Partition
Manager CLPR (Function of Virtual Partition Manager)
partitions the cache memory in the disk subsystem
into multiple virtual cache and assigns the
partitioned virtual cache for each use. If a large
amount of cache is required for a specific use, it can
minimize the impact on other uses. The CLPR
function works as follows depending on whether
SOM 454 is set to ON or OFF.
Mode 454 = OFF (default):
The amount of the entire destage processing is
periodically determined by using the highest
workload of all CLPRs (*a). (The larger the workload
is, the larger the amount of the entire destage
processing becomes.)
*a: (Write Pending capacity of CLPR#x) ÷ (Cache
capacity of CLPR#x), x=0 to 31
CLPR whose value above is the highest of all
CLPRs
Because the destage processing would be
accelerated depending on CLPR with high workload,
when the workload in a specific CLPR increases, the
risk of host I/O halt would be reduced.
Therefore, set Mode 454 to OFF in most cases.
Mode 454 = ON:
The amount of the entire destage processing is
periodically determined by using the workload of
the entire system (*b). (The larger the workload is,
the larger the amount of the entire destage
processing becomes.)
*b: (Write Pending capacity of the entire system) ÷
(Cache capacity of the entire system)
Because the destage processing would not be
accelerated even if CLPR has high workload, when
the workload in a specific CLPR increases, the risk
of host I/O halt would be increased. Therefore, it is
limited to set Mode 454 to ON only when a CLPR has
constant high workload and it gives priority to I/O OFF
Mode Category Description Default MCU/RCU