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:
Jul. 07, 2020
Filed:
Jul. 21, 2017
Emc Ip Holding Company Llc, Hopkinton, MA (US);
Ying Hu, Northborough, MA (US);
Xiangping Chen, Sherborn, MA (US);
EMC IP Holding Company LLC, Hopkinton, MA (US);
Abstract
A storage system comprises a storage device and metadata journal comprising metadata configured to store information associated with changes to information stored on the storage device. Dirty tree (DT) metadata pages, each corresponding to information written to the storage device from the metadata journal, are stored on the storage device. DT pages are read and scanned to detect if any DT metadata page comprises an entry having an invalid snap group ID associated with a given offset. For each detected DT metadata page comprising a respective invalid snap group ID, a corresponding fake journal entry is created in metadata journal and configured to point to the respective DT metadata page comprising the invalid snap group ID and given offset. The fake journal entry is configured so that, when the metadata journal is destaged to the storage device, the invalid snap group ID is reset to nonexistent.