Patent ID: 7917475

Claim:
A method comprising: continuously shadowing one or more live servers using at least one near-line server coupled to the one or more live servers, the live servers including data that provides services to a plurality of clients, wherein the at least one near-line server continuously shadows operations of the one or more live servers when providing the services to the plurality of clients; generating and maintaining a replica of the data during the shadowing using the at least one near-line server including maintaining the replica of the data on the at least one near-line server, wherein the generating and maintaining comprises generating write-ahead logs by the one or more live servers and receiving the write-ahead logs by the at least one near-line server, the near-line server updating the replica by applying the write-ahead logs to the replica; and automatically transferring the replica of the data to one or more standby servers, wherein the replica includes one or more portions of the data of the live servers, which are coupled to the at least one near-line server in response to an event of the one or more standby servers, wherein the event comprises a migration event that includes migration from a first version of at least one application hosted by the live servers to a second version of the application.