User guide

System option modes B–5
Hitachi Unified Storage VM Block Module Hardware User Guide
449 Universal
Replicator
Detecting and monitoring path blockade between MCU
and RCU of Universal Replicator<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 SOM454 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