Determining space to release in a target volume to which tracks from a source volume are mirrored

摘要

Provided are a computer program product, system, and method for determining space to release in a target volume to which tracks from a source volume are mirrored. A copy of a source volume table for the source volume providing a state of the tracks in the source volume for a consistency group is received. Tracks received from the source volume are written to the target volume to form the consistency group of tracks in the source volume at the target volume. A determination is made of tracks available to release from the copy of the source volume table and space allocated to the determined tracks is replaced. A point-in-time copy is created of the target volume for the consistency group. Complete is returned to forming the consistency group in response to releasing the space and creating the point-in-time copy.