When the mirrored point in time copy fails, at that point in time all the data for making the source and target of the point in time copy consistent is available on secondary volumes at disaster recovery site. The data for the source and target of the failed point in time copy are logically and physically equal at that point in time. This logical relationship can be maintained, and protected against ongoing physical updates to the affected tracks on the source secondary volume, by first reading the affected tracks from the source secondary volume, copying the data to the target secondary volume, and then writing the updated track to the source secondary volume.