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:
Jun. 19, 2012
Filed:
Sep. 28, 2010
Sitaram Pawar, Shrewsbury, MA (US);
Philippe Armangau, Acton, MA (US);
Yubing Wang, Holden, MA (US);
Christopher Seibel, Walpole, MA (US);
Soumyadeep Sen, Highland Park, NJ (US);
Sitaram Pawar, Shrewsbury, MA (US);
Philippe Armangau, Acton, MA (US);
Yubing Wang, Holden, MA (US);
Christopher Seibel, Walpole, MA (US);
Soumyadeep Sen, Highland Park, NJ (US);
EMC Corporation, Hopkinton, MA (US);
Abstract
A file server has an extent cache of pointers to leaf-level indirect blocks containing file mapping metadata. The extent cache improves file access read and write performance by returning a mapping for the data blocks to be read or written without having to iterate through intermediate level indirect blocks of the file. In addition, the extent cache contains pointers to the leaf-level indirect blocks in the file system cache. Therefore, in most cases, the time spent looking up pointers in the extent cache is offset by a reduction in the time that would otherwise be spent in locating the leaf-level indirect blocks in the file system cache. In a preferred implementation, the extent cache has a first least recently used (LRU) list and cache entry allocation for production files, and a second LRU list and cache entry allocation for snapshot copies of the production files.