Patent ID: 7197520

Claim:
A system, comprising: one or more data storage devices comprising a file system; one or more data backup devices; and a two-tier backup mechanism configured to: determine static data in the file system, wherein static data are data in the file system that have not been modified for a specified period, wherein the static data includes static copied data for which a specified number of copies have been previously backed up to second-tier backup media and candidate static data for which less than a specified number of copies have been previously backed up to the second-tier backup media; periodically or aperiodically back up the candidate static data from the file system to the second-tier backup media on the data backup devices; periodically or aperiodically back up dynamic data and the candidate static data from the file system to first-tier backup media on the data backup devices, wherein the dynamic data are data in the file system that have been created or modified in the specified period; and periodically or aperiodically back up only metadata for the static copied data from the file system to the first-tier backup media.