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:
Nov. 27, 2007
Filed:
Jan. 21, 2005
Katsumi Hirezaki, Odawara, JP;
Tetsuya Shirogane, Yokohama, JP;
Katsumi Hirezaki, Odawara, JP;
Tetsuya Shirogane, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
The present invention suppresses the generation of redundant I/O and improves the response to the host during data migration. When migrating data from the migration source volume to the migration destination volume, the access destination of the host is switched to the second storage device. When data requested by the host has not yet been migrated, data is read from the first storage device. When the frequency of access to the non-migrated area reaches a prescribed value, the target IP address is changed and discovery is implemented so as to switch the access destination of the host to the first storage device. When the frequency of access to the migrated area in the first storage device reaches a prescribed value, the access destination of the host is switched to the second storage device. The access destination of the host is controlled based on the data migration state and access state, and the generation of redundant I/O can be suppressed.