Replication: Transactional Replication Over WAN

A lot of users have wondered about the performance latency transactional replication suffers over WAN.

After analyzing / discussing this within the teams, here are the main points one should take into consideration when deciding / testing this type of implementation:

Should you notice performance degradation when testing your transactional replication over WAN, please verify the following:

1. Where is the latency occurring? Could it be an issue on the publisher / subscriber (example:blocking)

2. Verify that the @status of the articles published have the value of 16 or 24. Please see previous post in regards to this in order to understand the reason for performance benefit.

3. Disable offload TCP Checksum

    https://msdn.microsoft.com/en-us/library/aa938424.aspx

4. Disable TCP Chimney

    https://blogs.msdn.com/psssql/archive/2008/10/01/windows-scalable-networking-pack-possible-performance-and-concurrency-impacts-to-sql-server-workloads.aspx

5. Use a PULL subscription instead of a PUSH

6. Should the above 5 options not help in the performance, I would highly recommend the following:

    Geo-Replication Performance Gains with Microsoft SQL Server 2008 Running on Windows Server 2008

    https://technet.microsoft.com/en-us/library/dd263442.aspx