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Functional and Operational Characteristics 3-17
Hitachi Universal Storage Platform V/VM User and Reference Guide
Mode Category Function Default MCU/RCU
676 Audit Log Store an audit log on the system disk as specified by the user.
Mode 676 = ON: Store an audit log onto the system disk.
Mode 676 = OFF: Do not store an audit log onto the system
disk.
OFF –
677
OPEN and
mainframe
This option is used not to perform SM backup for saving battery
consumption after planned PS Off.
Mode 677 = ON: Mode 677 is available only when Mode 460 is
ON.
When planned PS Off ends normally and the SM information is
successfully saved in SVP, the following operations are
performed according to the model:
USP V, USP VM model: Battery is not used for SM backup.
NSC model: BASE PCB is powered off.
Mode 677 = OFF: Although planned PS Off ends normally,
battery is used for SM backup.
Note: This option is recommended when PS Off that exceeds
the backup time is performed, or where NSC model is used.
OFF MCU/RCU
685
OPEN and
mainframe
This option treats the blocakde of cache module group as that
of cache PCB to prevent performance degradation.
Mode 685 = ON: Cache module group blockade is treated as
Cache PCB blockade.
Mode 685 = OFF: Cache module group blockade is treated as
Cache PCB blockade when the blocked part reaches 75% of the
Cache capacity.
Notes:
This mode must not be set to ON in the device containing
only two Cache PCBs because the performance greatly
degrades with the device where only two Cache PCBs are
mounted since only one side of the cluster can be used due
to the Cache PCB blockade.
Since the failure of a cache module group is treated as the
failure of a cache PCB, the unavailable cache capacity is the
capacity of the entire PCB, instead of that of the failed
module group.
OFF MCU/RCU
689
TrueCopy and
TrueCopy for z/OS
This option is used to prevent the initial copy operation when
the Write Pending rate on RCU exceeds 60%.
Mode 689 = ON: The initial copy operation is prevented when
the Write Pending rate on RCU exceeds 60%.
Mode 689 = OFF: The initial copy operation is not prevented
when the Write Pending rate on RCU exceeds 60% (the same
as before).
Notes:
This mode can be set online.
The micro-programs on both MCU and RCU must support
this mode.
This mode should be set per customer’s requests.
If the Write Pending status long keeps 60% or more on RCU,
it takes extra time for the initial copy to be completed by
making up for the prevented copy operation.
OFF MCU/RCU