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3-18 Functional and Operational Characteristics
Hitachi Universal Storage Platform V/VM User and Reference Guide
Mode Category Function Default 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:
When CLPR of JNL-Volume exceeds 60%, Read JNL is
prevented.
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).
Notes:
This mode can be set online.
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.
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
697
TrueCopy Async,
TrueCopy for z/OS
Async,
ShadowImage,
ShadowImage for
z/OS
This option prevents the SI Split command execution when the
coordinated TCA pair status is Suspend, and its Consistency
state is not guaranteed.
Mode 697 = ON: SI Split is not executed when the coordinated
TCA pair status is Suspend, and its Consistency state is not
guaranteed.
Mode 697 = OFF: SI Split is executed regardless of the pair
status or Consistency state of the coordinated TCA.
Note: This option should be applied only to prevent SI Split
when the following conditions 1 and 2, or 1 and 3 are met.
1. TCA S-VOL and SI P-VOL coexist (for either mainframe or
open).
2. The TCA that is coordinated with SI has not been in
Suspend.
3. The TCA that is coordinated with SI is in Suspend, and its
Consistency is not in the latest state.
OFF MCU/RCU
701
Universal Volume
Manager
This option is used to issue the Read command at the LU
discovery operation using UVM.
Mode 701 = ON: The Read command is issued at the LU
discovery operation.
Mode 701 = OFF: The Read command is not issued at the LU
discovery operation.
Notes:
When the Open LDEV Guard attribute (VMA) is defined on an
external device, set the system option to ON.
When this option is set to ON, it takes longer time to
complete the LU discovery. The amount of time depends on
external storages.
With this system option OFF, if searching for external
devices with VMA set, the VMA information cannot be read.
OFF –