DLm0548E Device NNNN Volume VVVVVV GR RUN Replication Refresh Error Timed Out

NOTE: This article is specific to DLm0548E for GR=RUN device:

DLm0548E: Device nnnn volume vvvvvv GR=RUN replication-refresh error: timed out (2700 seconds)

Data replication failed to complete within the GR TIMEOUT period (Default Is 2700 Seconds, Which Equals 45 Minutes).

NOTE: Unlike "Guaranteed Replication" (GR=YES), Replication on RUN (GR=RUN) does not provide the "Guaranteed" behavior:
The host sends the RUN command after the host application completes. Even though Virtuent blocks on the Rewind-Unload (RUN) command and returns an equipment check if the replication-refresh fails for any reason. The host application cannot detect whether the replication-refresh completed successfully or with an error because it has already finished. That is, an error status that is returned to the RUN command does not cause the host job to abend. It continues as normal, and the subsequent job steps are run.

DLm0548E message is not necessarily an indication of a problem or error with GR=RUN. Predominantly, data replication is taking longer than usual due to overloaded bandwidth or unusually large number of file changes (that is, factors external to DLm). 

If a more persisting issue is suspected, contact Dell Support for assistance.

Mainframe jobs continue to run (see the 'Cause' statement), but GR=RUN jobs show increased elapse time. This is due to job termination requiring tape drive deallocation, which in turn requires replication-refresh completion or UNIT CHECK event for GR=RUN timeout. 
For z/OS, the UNIT CHECK event is typically recorded in mainframe syslog as message IOS000I reporting Equipment Check (EQC) for the virtual tape address.

This condition is discussed in detail in the Disk Library for mainframe (DLm) User Guide; Guaranteed Replication Chapter.