1. A method comprising: generating, by a storage server, a series of archives of subset of a data storage, each archive of the series of archives being stored in the data storage; releasing an older archive in the series of archives from the data storage at an end of a period of time after a new archive in the series of archives is generated; and generating a point-in-time image of the whole data storage after the older archive in the series of archives is released, wherein the point-in-time image includes a plurality of archives, and wherein data captured by the point-in-time image includes data contained in the new archive.