The system issues I/O to the storage subsystems when PPRC pairs
are establishing and ending as part of P/DAS functions. If a storage
subsystem I/O fails during these functions, MVS issues the following
error message:
IGF512I SWAP FROM ssss TERMINATED - SWAP FAILED DUE TO I/O ERROR
P/DAS writes this message to the system operator log and returns
error code 16 to the system.