Hitachi Universal Storage Platform VM - Manual (Page 69)

Functional and Operational Characteristics 3-25
Hitachi Universal Storage Platform V/VM User and Reference Guide
Mode Category Function Default MCU/RCU
689 TrueCopy Async
and TrueCopy for
z/OS Async 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 and resync copy operations
are prevented when the Write Pending rate on RCU exceeds
60%.
Mode 689 = OFF: The initial copy and resync copy operations
are not prevented when the Write Pending rate on RCU
exceeds 60% (the same as before).
Note:
ƒ This mode can be set online.
ƒ The micro-programs on both MCU and RCU must support
this mode.
ƒ This mode should be set per customer’s requests.
ƒ If the Write Pending status long keeps 60% or more on
RCU, it takes extra time for the initial copy and resync copy
to be completed by making up for the prevented copy
operation.
OFF MCU/RCU
690 Universal
Replicator and
Universal
Replicator for z/OS This option is used to prevent Read JNL or JNL Restore when
the Write Pending rate on RCU exceeds 60% as follows:
ƒ When CLPR of JNL-Volume exceeds 60%, Read JNL is
prevented.
ƒ When CLPR of Data (secondary)-Volume exceeds 60%, JNL
Restore is prevented.
Mode 690 = ON: Read JNL or JNL Restore is prevented when
the Write Pending rate on RCU exceeds 60%.
Mode 690 = OFF: Read JNL or JNL Restore is not prevented
when the Write Pending rate on RCU exceeds 60% (the same
as before).
Note:
ƒ This mode can be set online.
ƒ This mode should be set per customer’s requests.
ƒ 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.
ƒ If the Write Pending status long keeps 60% or more on
RCU, the pair status may become Suspend due to the JNL-
Vol being full.
OFF RCU