The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 21, 2015
Filed:
Oct. 05, 2012
Hitachi, Ltd., Tokyo, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A NAS device providing a snapshot function for executing CoW processing in multiple successive block units is provided, wherein upon restoring a file saved in a file system sharing from a snapshot, the speed for restoring files is enhanced by restoring only data blocks that have been changed within the data blocks constituting a file, to thereby reduce the amount of data being restored and cut down CoW processing. Upon restoring a file stored in file system sharing from a snapshot file, data blocks storing different data between the restore source file and the restore destination file are specified based on a differential map table and a differential block table, and only the specified data blocks are restored. Further, upon restoring data from a file other than the snapshot, the data blocks constituting the restore source file and the restore destination file are compared, and only the data blocks storing different data are restored.