Hitachi Virtual Storage Platform F400, System Administrator Manual, Page: 304 / 368

Mode Category Description Default MCU/RCU
689 TrueCopy
global-active
device
Allows you to slow the initial copy and resync
operations when the write-pending rate on the RCU
exceeds 60%.
Mode 689 = ON: The initial copy and resync copy
operations are slowed down when the Write Pending
rate on RCU exceeds 60%.
If the CLPR write pending rate where the initial copy
target secondary volume belongs to is not over 60%
but that of MP PCB where the S-VOL belongs to is
over 60%, the initial copy operation is slowed down.
Mode 689 = OFF (default): The initial copy and
resync copy operations are not slowed down when
the Write Pending rate on RCU exceeds 60% (the
same as before).
Notes:
1. This SOM can be set online.
2. The micro-programs on both MCU and RCU
must support this SOM.
3. This SOM should be set when requested by the
user.
4. Setting this SOM to ON is recommended when
GAD is installed, as the performance
degradation is more likely to occur due to
active-active I/Os.
5. If the write-pending status remains at 60% or
higher on the RCU for a long time, it takes extra
time for the initial copy and resync copy to be
completed due to the slower copy operations.
6. Do not set this SOM if the primary or secondary
system is connected to USP V/VM with
microcode earlier than 60-02-xx-xx/xx. If this
SOM is applied and the write-pending rate
reaches 60%, pair suspend might occur.
7. As this SOM is enabled per storage system, in an
environment where TC and GAD are used, this
SOM is applied to both program products. When
GAD is installed in a storage system that already
uses TC, TC initial copy might take longer time.
OFF Both
System option modes
Appendix B: System option modes
System Administrator Guide for VSP Gx00 models and VSP Fx00 models 304