Patent ID: 7353335

Claim:
A storage control method, which is performed by a storage system comprising a database, wherein said storage system comprises a first storage subsystem and a second storage subsystem, said first storage subsystem comprises a first DB storage device capable of storing a database, and a first log storage device capable of storing a log of said database; and said second storage subsystem comprises a second DB storage device capable of being paired with said first DB storage device, and a second log storage device capable of being paired with said first log storage device, and wherein, said first storage subsystem is constituted such that, when a DB-pair state, which is the pair state of said first DB storage device and said second DB storage device, is a pair-split state, and a difference occurs between said first DB storage device and said second DB storage device, the difference is managed, and when the pair-split state is cancelled, said first storage subsystem, by sending said managed difference to said second storage subsystem, can cause said difference to be updated in said second DB storage device, thereby doing away with the difference between said first DB storage device and said second DB storage device, said storage control method comprising the steps of: creating, when, as a log control mode which is a mode related to controlling a log of a database, are provided a logless mode, which is a mode in which a log comprising at least the update history of said database is not created even if this database is updated during a transaction, and a mode, which differs from said logless mode, and a transaction is executed in said logless mode, a logless-start log, which is a log denoting the start of said logless mode, at the start of the transaction, and writing the logless-start log to said first log storage device by issuing the logless-start log to said first log storage device; writing said logless-start log, which is written to said first log storage device, to said second log storage device by sending the logless-start log to said second storage subsystem from said first storage subsystem; executing DB updating for updating a plurality of times the database of said first DB storage device by issuing a plurality of data respectively to the database; canceling a pair-split state between said first DB storage device and said second DB storage device either prior to the start or subsequent to the completion of said DB updating while a commenced transaction is being executed; creating, subsequent to the end of said DB updating, a logless-end log, which is a log denoting the termination of said logless mode, and writing the logless-end log to said first log storage device when the difference between said first DB storage device and said second DB storage device has been done away with; and writing said logless-end log, which is written to said first log storage device, to said second log storage device by sending the logless-end log to said second storage subsystem from said first storage subsystem.