Data base duplication method of using remote copy and database duplication storage subsystem thereof

DETAILED DESCRIPTION With the intention of reducing the data transfer time based on the copying of DB table data by use of the scheme of automatic prior data duplication, such as the remote copy function, of the disk system, instead of the data file transfer by the FTP or the like, it is an object of the present invention to provide a scheme of certifying the matching of copied DB table data of the copy destination.
This scheme is capable of not only reducing the data transfer time, but also shifting the data extraction process of the trunk business system to the data ware house system thereby to prevent the deterioration of response of the trunk business system which would arise at the data extraction process.
In order to achieve the above objective, the present invention resides in a data duplication control method for a system which includes a main system having a first processor system in which a first DBMS operates and a first storage subsystem connected to the first processor system and a subordinate system having a second processor system in which a second DBMS operates and a second storage subsystem connected to the second processor system, with the first and second storage subsystems being connected to each other, the method comprising a step, which is implemented by the first DBMS by being directed by the first processor system, of overwriting database table data (will be termed "DB table data") which is stored in a cache and put in and out by the first DBMS to the database table (will be termed "DB table") of the first storage subsystem, and holding the updating of the DB table data in the DB table against a subsequent request of updating of the DB table data, and a step, which is implemented by the first storage subsystem by being directed by the first processor system, of transferring and copying the DB table data of the DB table of the self storage subsystem to the DB table of the second storage subsystem thereby to duplicate the DB table data, and suspending the subsequent transfer of DB table data so that the DB tables of the first and second storage subsystems are in a state of matching, thereby enabling the second DBMS to refer the copied DB table in a state of matching