Hitachi TrueCopy for IBM z/OS User and Reference Guide (T5211-96001, June 2007)

5-14 Performing TrueCopy for z/OS Configuration Operations
Hitachi Universal Storage Platform V TrueCopy for IBM z/OS User’s Guide
Caution: If TrueCopy for z/OS pairs are suspended because the number of
paths has dropped below this setting, the M-VOL fence level pair option
determines whether the TrueCopy for z/OS Sync M-VOLs are fenced (i.e.,
reject all write operations).
The RIO MIH Time setting specifies the time value for the remote I/O (RIO)
missing interrupt handler (MIH), which is the wait time until data transfer from
the MCU to RCU is complete. The RIO MIH time value must be from 10 to 100
seconds. The default setting is 15 seconds.
The Incident of RCU option allows you to specify which host(s) the RCUs will
report link incident records to. When to any host is selected, the RCUs will
send link incident records to all RCU hosts and to all MCU hosts. When only to
RCU host is selected, the RCUs send link incident records only to the RCU
host(s). Make sure that RCU link incidents are reported to the proper host(s)
so that corrective action, if needed, can be taken. The to any host setting is
recommended when TCz is being used for disaster recovery purposes.
The FREEZE Option setting allows you to enable or disable support for the
CGROUP (FREEZE/ RUN) PPRC TSO command. The FREEZE option is available
only when PPRC support = Yes. If you select Enable, the MCU will accept and
perform the CGROUP command. If you select Disable, the MCU will reject the
CGROUP command.
Note: Enable the FREEZE option only after all MCU-RCU paths have been
added.
Note: The PPRC commands do not allow you to change the RCU options.
The Round Trip Time setting is used for Initial Copy operations. This setting
gives a priority to a remote I/O for an update copy operation.
When an Initial Copy operation is in progress, the copy pace is automatically
adjusted based on the value (the actual time required for the initial copy),
which can be obtained by subtracting the specified Round Trip time (obtained
using the formula below) from the remote I/O response time. The actual time
required for the initial copy operation is large, it means that the workload of
the update copy is relatively high. Therefore, the copy pace of the initial copy
will be slowed. When the time is relatively small, the copy pace will speed up
to the specified value. In this way, we can curb the influence of the exclusive
line use in the initial copy operation on the host performance.
Note: This option is available only in the case of TCz pairs (In the case of
TCzA pairs, this option value is invalid).