Patent ID: 7483926

Claim:
A computer program product for implementing a method for backing up and restoring data, the computer program product comprising one or more recordable-type computer-readable storage media having stored thereon computer-executable instructions that, when executed by one or more processors of the computing system, cause the computing system to perform the method, the method comprising: maintaining a first mapping that maps files stored in a first volume of a first computer in a first filing format to files stored in a second volume of a second computer in a second filing format, the first mapping including a plurality of mapping information portions, wherein at least one of the portions includes proprietary mapping information and at least one of the portions includes public mapping information indicating which files of the first volume have been mapped to files of the second volume, wherein the second volume stores a copy of one or more data files of the first volume in a second filing format different than the first filing format used to store files in the first computer, wherein the copy is updated as the data files of the first volume are updated; backing up data files of the second volume to a storage library in a manner so as to appear as to have come directly from the first computer, the backing up comprising storing the data files according to the first filing format of the first computer as indicated by the public mapping information, together with the mappings between the data files of the first volume of the first computer and the data files of the second volume of the second computer; restoring one or more data files from the storage library to the first volume of the first computer using the first filing format such that files of the first computer are directly restorable from the storage library without accessing the files or mappings of the second computer; taking a snapshot of the first volume of the first computer, wherein the snapshot is viewed as a separate volume by the first computer operating system and any executing applications; maintaining a second mapping that maps the snapshot to the second volume on the second computer; backing up the snapshot on the second volume according to the second mapping using a proprietary format, the second mapping including an indication of which first computer system volumes are backed up on the second server; backing up the snapshot stored on the second volume to a third computer system using a public format, such that, in each instance where a difference between the proprietary format and the public format is detected, a file mapping change is inserted; and restoring at least some portions of data from the snapshot to at least one of the first computer according to the proprietary format and the second computer using the public format.