Patent ID: 8782362

Claim:
A computer program product for performing a write to a volume x in a cyclic point-in-time-copy architecture, the computer program product comprising a non-transitory computer-readable storage medium having computer-usable program code embodied therein, the computer-usable program code comprising: computer-usable program code to determine whether the volume x has a child volume, wherein each of the volume x and the child volume have a target bit map (TBM) associated therewith; computer-usable program code to determine whether the TBMs of both the volume x and the child volume are set: computer-usable program code to, if the TBMs are set, find a higher source (HS) volume from which to copy data to the child volume, wherein finding the HS volume comprises finding a source volume associated with the volume x, determining a downstream mapping relationship between the source volume and the volume x, and determining if an upstream mapping relationship from the source volume was created after the downstream mapping relationship, wherein the source volume is determined to be the HS volume if the upstream mapping relationship from the source volume was created after the downstream mapping relationship; computer-usable program code to determine whether the HS volume and the child volume are the same volume; computer-usable program code to copy the data from the HS volume to the child volume if the HS volume and the child volume are not the same volume; and computer-usable program code to perform the write on the volume x.