When you set up the TC association between the primary and secondary systems, you specify the minimum number of remote paths to the secondary system using the Minimum Number of Paths option (range = 1-8, default = 1). If the number of remote paths in Normal status drops below the specified minimum, the primary storage system splits the pairs to prevent remote copy operations from impacting host performance in the primary storage system.
- To maintain host performance in the primary storage system, set the minimum number of remote paths to at least 2 to ensure that remote copy operations are performed only when multiple paths are available.
- To continue remote copy operations even when there is only one remote path in Normal status, set the minimum number of remote paths to 1. Use this setting only when keeping pairs synchronized is more important than maintaining high performance in the primary storage system.
Note: You can use the fence level option to keep a P-VOL and S-VOL synchronized even if the pair is split because the number of remote paths drops below the minimum setting. The fence level setting, which you specify when you create a pair, determines whether the P-VOL continues to accept write I/Os after the pair is split due to an error. For details, see Allowing I/O to the P-VOL after a split: Fence Level options.