Reducing failback performance duration in data replication systems

A computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions readable and/or executable by a processor to cause the processor to:

• in response to determining that a primary cluster at a first storage location has gone offline, establish, by the processor, a recovery cluster at a second storage location as an acting primary cluster;
• in response to determining that the primary cluster at the first storage location is back online, synch, by the processor, the acting primary cluster with the online primary cluster by:
• capturing a snapshot of the acting primary cluster,
• pausing a normal queue of the acting primary cluster,
• comparing the snapshot of the acting primary cluster with a most recent snapshot of the online primary cluster,
• adding each difference between the snapshot of the acting primary cluster and the most recent snapshot of the online primary cluster to a priority queue of the acting primary cluster, and
• transmitting each of the differences in the priority queue to the online primary cluster;
• and
• in response to determining that each of the differences in the priority queue have been transmitted to the online primary cluster, transmit, by the processor, entries in the normal queue to the online primary cluster.

A system, comprising:

• a processor;
• and
• logic executable by the processor, the logic being configured to:
• in response to determining that a primary cluster at a first storage location has gone offline, establish, by the processor, a recovery cluster at a second storage location as an acting primary cluster;
• in response to determining that the primary cluster at the first storage location is back online, synch, by the processor, the acting primary cluster with the online primary cluster by:
• capturing a snapshot of the acting primary cluster,
• pausing a normal queue of the acting primary cluster,
• comparing the snapshot of the acting primary cluster with a most recent snapshot of the online primary cluster,
• adding each difference between the snapshot of the acting primary cluster and the most recent snapshot of the online primary cluster to a priority queue of the acting primary cluster, and
• transmitting each of the differences in the priority queue to the online primary cluster;
• and
• in response to determining that each of the differences in the priority queue have been transmitted to the online primary cluster, transmit, by the processor, entries in the normal queue to the online primary cluster.