Cascaded, point-in-time-copy architecture with data deduplication

A method for performing a read to a volume x in a cascaded point-in-time-copy architecture, the method comprising:

• reading a target bit map (TBM) associated with the volume x;
• determining whether the TBM is set;
• if the TBM is set, finding a higher source (HS) volume from which to read data, wherein finding the HS volume comprises travelling up the cascaded architecture until the source of the data is found;
• and
• reading the data from the HS volume.

A computer program product for performing a write to a volume x in a cascaded point-in-time-copy architecture, the computer program product comprising a 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 travelling up the cascaded architecture until the source of the data is found;
• computer-usable program code to copy the data from the HS volume to the child volume;
• and
• computer-usable program code to perform the write on the volume x.