Abstract: A method is provided for asynchronously tracking the replication of data writes from an application that is subject to system and network failure, to a standby data processing unit located at a standby site. The method includes the step of enabling access to sequence numbers created for use in replication of the data writes. Another step is sending the data writes to a remote mirroring module. Next is assigning sequence numbers to each data write accepted. It can then be determined when data writes at a local site have been successfully replicated at the standby site by correlating the most recent local write sequence number and most recent replication sequence number. An additional step is initiating replication of the data writes for which replication has not taken place.