Patent ID: 8782464

Claim:
A system for storing data, the system comprising: a first main server including a cache and a non-volatile storage; a second main server in communication with the first main server, the second main server including a cache and a non-volatile storage; a standby server in communication with the first main server and the second main server; and shared input/output adapters in communication with the standby server, the first main server, and the second main server, wherein: the storage system is configured to operate as a dual node system, the cache of the first main server includes a copy of data corresponding to the first main server and the non-volatile storage of the first main server includes a copy of modified cache data of the second main server; the cache of the second main server includes a copy of data corresponding to the second main server and the non-volatile storage of the second main server includes a copy of modified cache data of the first main server; during a failback to service condition of the second main server, the modified cache data of the second main server stored on the non-volatile storage of the first main server is destaged through the shared input/output adapters and shared to other storage areas and the first main server sends communication to the standby server; the standby server is adapted to activate in response to receiving the communication from the first main server of a fail mode of the second main server and to provide continued operation by employing the shared I/O adapters; and the fail mode comprises a failover mode, and modified data is destaged from the first main server during the fail mode of the second main server, and the standby server is activated after destaging data.