Patent ID: 9436558
Filing Date: 2016-09-06
CPC Classification: G06F

Claim Text:
1. A method for data backup, the method comprising: determining a set of data blocks subject to a backup; for each data block generating a hash value and a location pointer; accumulating the hash values into a set; sorting the hash values within the set; comparing the hash values against hash values stored in a hash table, wherein the hash values stored in the hash table correspond to previously backed up unique data blocks; storing location pointers of the data blocks, if the corresponding hash values match the hash values from the hash table; deleting the matching hash value from the set; writing remaining unique hash values into the hash table; and identifying redundant data block locations of data blocks in the backup data storage that are absent from the hash table; dividing the backup data storage into containers; determining a number of redundant data blocks in each container; and determining whether to delete a redundant data block based on a ratio of the number of redundant data blocks in a corresponding container to the number of used data blocks in the corresponding container.