Patent ID: 6771843
Filing Date: 2004-08-03
Classification: G06F

Abstract:
A method of managing point-in-time data images of a base volume containing data in a data storage system, the base volume being used for data storage read and write accesses, states of the base volume at various points in time being preserved by a snapshot technique that forms snapshot volumes from the base volume at the points in time, comprising the steps of:forming a plurality of the snapshot volumes from the base volume at a plurality of the points in time, the plurality of snapshot volumes including a rollback snapshot volume and a later-formed snapshot volume formed after the rollback snapshot volume was formed; copying first data from the base volume to the rollback snapshot volume; replacing the first data with second data in the base volume before forming the later-formed snapshot volume; selecting the rollback snapshot volume for rolling back the first data to the base volume to replace the second data; copying the second data from the base volume to the later-formed snapshot volume; and replacing the second data with the first data in the base volume by copying the first data from the rollback snapshot volume back to the base volume.