Patent ID: 7340637

Claim:
A method for duplicating a first and a second server in a system, comprising: storing an application used for a service task and corresponding application data in each of a first and a second storage device; responding to a service request by storing the service request and output data as a data log in each of a first and a second stack; forming an address space that is the same in each of a first and a second shared memory, wherein the first server comprises the first storage device, the first stack, and the first shared memory, wherein the second server comprises the second storage device, the second stack, and the second shared memory, and wherein the first and the second server are configured to connect to a network and are assigned the same network address; and passing the service request from the first server to an application for updating application data received over the network after the service request is received, wherein the application is configured to process the service request and write the application data used during processing to each of the first and the second shared memory as recovery data, wherein the application is configured to store the recovery data written to the first and the second shared memory to the first and the second stack, wherein the second server is configured to update the application data by executing the application using the recovery data stored in the first and the second shared memory, wherein the application data stored on the first server is always identical to the application data stored on the second server.