Patent ID: 7421435
Filing Date: 2008-09-02
Classification: G06F,Y10S

Abstract:
1. A storage system comprising: a first disk array system coupled to a host computer including: a second disk array system coupled to the first disk array system including: a third disk array system coupled to the first disk array system including: the second disk array system includes a sixth volume related to a second portion of the second first drives and temporarily stores update data received from the first disk array system in the sixth volume before storing it in the fourth volume; the third disk array system includes a seventh volume related to a second portion of the third disk drives and temporarily stores the update data received from the first disk array system in the seventh volume before storing it in the fifth volume; the update data stored in the second volume is appended to first update information; the update data stored in the third volume is appended to second update information; if the update data stored in the sixth volume is stored in the fourth volume, the first update information is used to record a sequence of updates from the host computer; and if the update data stored in the seventh volume is stored in the fifth volume, the second update information includes common information included in the first update information used to record the sequence of updates from the host computer.