Hitachi Virtual Storage Platform G400 - Page 316

Mode Category Description Default MCU/RCU
784 TrueCopy
Global-active
de
vice
This SOM can reduce the MIH watch time of RI/O for
a TC or GAD pair internally so that update I/Os can
continue by using an alternate path without MIH or
time-out occurrence in the environment where
Mainframe host MIH is set to 15 seconds, or Open
host time-out time is short (15 seconds or less). This
SOM is eective at initial pair creation or Resync
operation for TC or GAD. (Not eective by just setting
this SOM to ON.)
This SOM is applied to TC and GAD. This SOM
supports Fibre remote copy paths but not iSCSI.
Mode 784 = ON: The MIH time of RIO is internally
reduced so that, even though a path failure occurs
between storage systems in the environment where
host MIH time is set to 15 seconds, update I/Os can
be processed by using an alternate path promptly,
lowering the possibility of host MIH occurrence.
Mode 784 = OFF (default): The operation is
processed in accordance with the TC or GAD
specication.
Notes:
1. This SOM is applied to the environment where
Mainframe host MIH time is set to 15 seconds.
2. This SOM is applied to the environment where
OPEN host time-out time is set to 15 seconds or
less.
3. This SOM is applied to reduce RI/O MIH time to
5 seconds.
4. This function is available for all the TC and GAD
pairs on the storage system, unable to specify
the pairs that are using this function or not.
5. For a TC or GAD pair with this SOM eective
(RI/O MIH time is 5 seconds), the setting of RI/O
MIH time made at RCU registration (default is 15
seconds, which can be changed within range
from 10 to 100 seconds) is invalid. However,
RI/O MIH time displayed on Device Manager -
Storage Navigator and CCI is not “5 seconds” but
is what set at RI/O registration.
6. If a failure occurs on the switched path between
storage systems, Mainframe host MIH or Open
server time-out may occur.
7. If an MP to which the path between storage
systems belongs is overloaded, switching to an
OFF Both
System option modes
Appendix B: System option modes
System Administrator Guide for VSP Gx00 models and VSP Fx00 models 316