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. 11, 2006
Filed:
Feb. 23, 2004
Masaki Aizawa, Odawara, JP;
Eiju Katsuragi, Odawara, JP;
Mikio Fukuoka, Odawara, JP;
Takeki Okamoto, Odawara, JP;
Masaki Aizawa, Odawara, JP;
Eiju Katsuragi, Odawara, JP;
Mikio Fukuoka, Odawara, JP;
Takeki Okamoto, Odawara, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
The invention is intended to reduce disk access during data transfer from a disk in which occurrence of failure is anticipated to a spare disk as much as possible so that occurrence of double-failure is prevented in advance. When occurrence of failure in a disk which configures a RAID group, contents stored in the disk is copied to the spared disk. Simultaneously, another RAID group is paired with the above described RAID group and a secondary volume is provided therein. A write request is directed to the secondary volume. A differential bitmap controls a update data. Data which is not updated is read out from the primary volume, and data which is already updated is read from the secondary volume. When data transfer is completed, contents stored in the secondary volume are copied to the primary volume.