Techniques for asynchronous data replication

摘要

Techniques for asynchronous data replication are presented. A bitmap records changes to selective blocks of data on a source between replication periods. During a replication, the bitmap is copied and used to acquire changed blocks from the source to write to a replica. Should a unprocessed block have a pending write detected during the replication, then that block is copied into cache from the source before the write is processed on the source. The pending write then processes against the source; the copied block is flushed to the replica; the original bitmap and copied bitmap are updated.