Patent ID: 7844852

Claim:
A data mirror cluster system comprising multiple server apparatuses connected via an interconnect with each other and one of multiple server apparatuses serving as an operation system and at least another one serving as a standby system, each of said server apparatuses comprising a database; a shared memory accessible from the server apparatuses, a memory driver for the operation system which determines every change in data of a database on the operation system and writes data representing the change in data stored in the database of the operation system to a shared memory of the operation system and for said every change in data of the database simultaneously writes the change in data stored in the database of the operation system to a shared memory existing in the standby server apparatus via the interconnect when an associated server apparatus is operating as the operation system; and a memory driver for the standby system which updates data stored in the database of the standby system based on data stored in said shared memory of the standby system which is stored by said operation system via the interconnect when the associated server apparatus is operating as the standby system.