• Pair operations cannot be performed on volumes that do not have an LU path. Before performing pair operations, make sure that the volumes to be assigned to pairs have at least one LU path defined.
• Pair operations cannot be performed during microcode/firmware exchange processing. Before performing pair operations, make sure that microcode/firmware exchange processing is complete.
• Pair operations cannot be performed when microcode/firmware exchange processing has been interrupted (for example, due to user cancellation or error). Make sure that microcode/firmware exchange processing has completed normally before performing pair operations.

• The availability ratio of the processor in the MP blade/unit to which the primary volume belongs is equal to or more than 70% on the storage system at the primary site.
• There is a large amount of inward traffic of update I/O to the primary volumes on the storage system at the primary site.
• The Write Pending of the MP blade/unit to which the secondary volume belongs is equal to or more than 65% on the storage system at the secondary site.

When you create or resynchronize the GAD pair, consider the above load status of the storage system at each site.