US Patent 10042714 Point-in-time copy on write for golden image

A system, method, and computer program product for managing storage volumes. A processor creates a first point-in-time copy cascade, where the first point-in-time copy cascade comprises a source volume, a first snapshot point-in-time copy volume, and a second snapshot point-in-time copy volume; the first volume is a snapshot copy of the source volume and the second volume is a snapshot copy of the first volume. A processor creates a third snapshot point-in-time copy volume from the first volume. A processor maps the third volume to create a second cascade, wherein the second cascade comprises the source volume, the first volume, and the third volume but not the second volume. A processor directs an I/O operation for the first copy volume to the third volume.