You can change remote connection options to optimize TrueCopy for Mainframe performance.
The following remote connection options affect how copy operations are performed:
- Number of minimum paths for a pair. You can find detailed information in Minimum number of remote paths option
- RIO MIH Time, which is the waiting time from when copy starts until when it ends. This value applies to the slots which received the request of copying data from the local storage system to the remote storage system.
- FREEZE option, which defines support for the CGROUP (FREEZE/ RUN) PPRC TSO command.
- Round trip time, which is the time limit for copying data to the S-VOL. For more information, see Round trip time option.
If the local storage system contains a TCz pair storing important data (for example, for disaster recovery), set the minimum number of paths to 1 (default). By doing so, TCz operations can continue even if there is only one path to the remote storage system. If you want to keep the performance of the local storage system at a high level, set the number of minimum paths to 2 or greater (the maximum number of paths per CU is 8).
If the number of normal paths becomes less than the minimum number of paths, the local storage system prevents the performance degradation of the host by splitting all the pairs that are affected by the insufficient number of paths. In addition, the fence level specified for the P-VOL determines whether fencing (rejection of all writes) is enabled or disabled on the TCz P-VOL (see Allowing I/O to the P-VOL after a split: Fence Level options).