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:
Sep. 04, 2012
Filed:
Mar. 05, 2008
Paresh Chatterjee, Fremont, CA (US);
Vijayarankan Muthirisavenugopal, Fremont, CA (US);
Srikumar Subramanian, Fremont, CA (US);
Ajit Narayanan, Fremont, CA (US);
Paresh Chatterjee, Fremont, CA (US);
Vijayarankan Muthirisavenugopal, Fremont, CA (US);
Srikumar Subramanian, Fremont, CA (US);
Ajit Narayanan, Fremont, CA (US);
American Megatrends, Inc., Norcross, GA (US);
Abstract
A method, system, apparatus, and computer-readable medium are provided for taking snapshots of a storage volume. According to aspects of one method, each snapshot is represented as a unique sequence number. Every fresh write access to a volume in a new snapshot lifetime is allocated a new section in the disk, called a provision, which is labeled with the sequence number. Read-modify-write operations are performed on a sub-provision level at the granularity of a chunk. Because each provision contains chunks with valid data and chunks with invalid data, a bitmap is utilized to identify the valid and invalid chunks with each provision. Provisions corresponding to different snapshots are arranged in a linked list. Branches from the linked list can be created for storing writable snapshots. Provisions may also be deleted and rolled back by manipulating the contents of the linked lists.