Patent ID: 6988176
Filing Date: 2006-01-17
Classification: G06F,Y10S

Abstract:
1. A method for duplexing data in a storage unit system for carrying out backup operation of data from a primary side system comprising one or more primary side control units to a secondary side system comprising a plurality of secondary side control units, the method comprising the steps of: adding time information relating to a write time to a data of a write request and storing the information in cache memory in the primary side control units when there is a write request from a processing unit to the primary side control units; transmitting the stored write data and the time information to the secondary side control units; storing the write data and the time information to cache memory in the secondary side control units; transmitting the time information stored in the cache memory in the secondary side control units to another secondary side control unit via a communication route for connecting the secondary side control units with each other; comparing the time information of a first secondary side control unit received from a first primary side control unit with a time information transmitted from the second secondary side control units, and transmitting an older time information to a next secondary side control unit via the communication route; circulating the older time information between the secondary side control units; and determining a data guarantee time for guaranteeing duplexing of the write data between the secondary side control units.