Emc IP Holding Company LLC

Emc Corporation

Emc IP Holding Corporation LLC

Anand Ghatnekar

Kedar Shrikrishna Patwardhan

Kedar Patwardhan

Systems and methods for adding backups to de-duplicated storage and for removing backups from de-duplicated storage are disclosed. Backups can be added to the de-duplicated storage with minimal reference count updates. Backup data sets can be removed without garbage collection processes being performed on the de-duplicated storage.

Storing de-duplicated data with minimal reference counts

Techniques to back up data are disclosed. In various embodiments, a copy of a free block map as of a first time associated with a first backup is stored in persistent data storage. Writes made subsequent to the first backup to blocks not listed as free in the copy of the free block map as of the first time are tracked in a persistently-stored change block tracking log. A free block map as of a second time and the previously-stored copy of the free block map as of the first time are used to determine which blocks listed as free in the free block map as of the first time have been written to since the first time. At least a subset of blocks determined to have been written to since the first time are including in an incremental backup.

Optimization to permit block based incremental backup across system reboot or crash

A cloud gateway (GW) device receives a first request for incremental backup from a client device over a LAN, where the first request includes a first file representing a difference between the incremental backup in view of a prior backup. In response, the cloud GW identifies a first base backup previously backed up to a cloud storage server over a WAN. A second request is transmitted to the cloud storage server over the WAN to copy the first base backup into a second base backup. A third request is transmitted to the cloud storage server over the WAN to replace a second file within the second base backup. The third request includes a second backup ID, a descriptor describing the file to be replaced, and content of the file received from the client without modifying the first file.

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Pune, India

Anand Ghatnekar