PREFETCHING SOURCE TRACKS FOR DESTAGING UPDATED TRACKS IN A COPY RELATIONSHIP

摘要

A point-in-time copy relationship associates tracks in a source storage with tracks in a target storage. The target storage stores the tracks in the source storage as of a point-in-time. A point-in-time copy relationship associates tracks in the source storage with tracks in the target storage, wherein the target storage stores the tracks in the source storage as of a point-in-time. A write request is received including an updated source track for a point-in-time source track in the source storage in the point-in-time copy relationship, wherein the point-in-time source track was in the source storage at the point-in-time the copy relationship was established. The updated source track is stored in a cache device. A prefetch request is sent to the source storage to prefetch the point-in-time source track in the source storage subject to the write request before destaging the updated source track to the source storage.