Patent ID: 7801860
Filing Date: 2010-09-21
Classification: G06F

Abstract:
1. A system switching control method that switches from multiple database servers of an executive system computer to multiple database servers of a standby system computer in a computer system in which the executive system computer and the standby system computer share a database in an external storage device, external of each of said executive and standby system computers, to execute Input/Output (I/O) processing request, said system switching control method comprising: registering order information in a storage device of said executive system computer that indicates an order in which the multiple database servers of said executive system computer are switched to the database servers of the standby system computer; detecting that a checkpoint occurred in one of the database servers of the executive system computer so that update to data in a cache memory of the data server in which the checkpoint occurred is reflected to the database in the external storage device to update the database in the latest state; changing the order information upon detection of the checkpoint so that a switching sequence of the database server of the executive system computer in which the checkpoint occurred follows a switching sequence of the other database servers; and executing system switching processing from the executive system computer to the standby system computer in accordance with the changed order information, wherein the order information is changed in accordance with the checkpoint occurrence time so that a switching order of the database server in which the checkpoint occurred is set to the last.