Managing a deletion of a volume referenced by a snapshot of a consistency group

A computer program product for managing a deletion of a volume referenced by a snapshot of a consistency group, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions readable by a storage system to cause the storage system to:

• designate a to-be deleted original volume as a ghost volume within a consistency group stored within the storage system, the consistency group, subsequent to the designation of the ghost volume, comprising the ghost volume and a plurality of original volumes;
• identify a preexisting point-in-time snapshot of the consistency group that existed prior to the designation of the ghost volume, the preexisting point-in-time snapshot, subsequent to the designation of the ghost volume, comprising a plurality of pointers that each point to a different one of the plurality of original volumes of the consistency group and an orphaned pointer that points to the ghost volume;
• subsequent to the designation of the ghost volume, take a present point-in-time snapshot of the consistency group, the present point-in-time snapshot consisting of a plurality of pointers that each point to a different one of the plurality of original volumes of the consistency group;
• and
• prevent deletion of the ghost volume from the storage system until there are no point-in-time snapshots of the consistency group that comprise a orphaned pointer that points to the ghost volume.

A storage system comprising:

• a consistency group repository comprising a consistency group that comprises a plurality of original volumes and a designated ghost volume;
• a snapshot repository comprising:
• a first point-in-time snapshot of the consistency group taken prior to the designation of the ghost volume, the first point-in-time snapshot comprising a first plurality of pointers that each point to a different one of the plurality of original volumes and an orphaned pointer that points to the ghost volume;
• a second point-in-time snapshot of the consistency group taken subsequent to the designation of the ghost volume, the second point-in-time snapshot consisting of a second plurality of pointers that each point to a different one of the plurality of original volumes;
• and
• a snapshot manager stored upon a computer readable storage medium within the storage system that when called by the storage system, causes the storage system to prevent deletion of the ghost volume from the storage system until there are no point-in-time snapshots of the consistency group that comprise a orphaned pointer that points to the ghost volume.