US Patent 7792802 Archiving logs with snapshots for data recovery

A method for archiving a log for a data storage system includes the steps of logging host inputs/outputs to the log, creating a snapshot of the log when it is full, resetting a next write offset to the start of the log after the snapshot is created while continuing the logging to the log, performing copy-on-write of the log to the snapshot, and archiving the snapshot to an archived log.