Recovering mirrored data after the failure of a computer using write requests
stored in a delta queue of an associated computer without transmitting all of the
mirrored data. A write request at a primary computer is stored in a delay buffer.
A copy of the write request is transmitted to a backup computer and stored in a
delta queue. The backup computer executes the copy of the write request and transmits
acknowledgement of the receipt of the write request to the primary computer. In
response to the acknowledgement, the primary computer executes the write request
stored in the delay buffer. The computers then exchange subsequent acknowledgements
of the write request execution, enabling the computers to delete the write requests.
If the primary computer fails, the primary computer recovers data by receiving
only the copies of write requests that remain stored in the delta queue of the
backup computer.