Mode Category Description Default MCU/RCU
454 Virtual
Partition
Manager
CLPR (function of Virtual Partition Manager)
partitions the cache memory in the stor
age system
into multiple virtual cache and assigns the
partitioned virtual cache for each use. If a large
amount of cache is required for a speciî ´c 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 of concerned
MPB) ÷ (Cache capacity of CLPR#x of concerned
MPB), 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 speciî ´c CLPR increases, the
risk of host I/O halt would be reduced.
Therefore, set SOM 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 of
concerned MPB) ÷ (Cache capacity of the entire
system of concerned MPB)
Caution: Because the destage processing would not
be accelerated even if CLPR has high workload, when
the workload in a speciî ´c CLPR increases, the risk of
host I/O halt would be increased. Therefore, set SOM
454 to ON only when a CLPR has constant high
workload and the I/O performance in a CLPR with
low workload has higher priority than host I/O halt in
the CLPR with high workload.
Notes:
OFF -
System option modes
Appendix B: System option modes
System Administrator Guide for VSP Gx00 models and VSP Fx00 models 295
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