US Patent 7797279 Merging of incremental data streams with prior backed-up data

New full backups are generated by combining an incremental backup with a previous full backup. A previous full backup is stored in a backup server in a hash file system format. A file server generates an incremental backup of a data set on the file server by identifying and dumping files/directories of the data set that are new/modified into a tar file that is sent to an accelerator. The accelerator parses the incremental backup tar file and converts it to a hash file system format that includes metadata, hash values, and new/modified data atomics. The accelerator merges the incremental backup into the previous full backup to generate a new full backup by altering metadata and hash values of a copy of the previous full backup such that the resulting metadata and hash values describe and point to new/modified directories and files as well as unmodified directories and files.