Sun Directory Server – Replication over WAN
Yesterday we had to modify a huge number of entries in our directory server environment. The updates were all done in one data center, and they went extremely fast. When I later went to check on the replication, I noticed the data was replicated much slower to the remote data center than I expected. Given that the other data center is a pretty decent WAN hop awa, I decided to try changing some of the replication agreement parameters. To do this you use:
dsconf set-repl-agmt-properties $suffix $property:$value
You can see more information on the properties and suggested values at the Replication Over a WAN page of the DSEE Admin Guide.
In our case, I did some quick experimenting and found the values suggested for WANs seemed to work pretty well and gave us about a 3x-4x boost in performance versus the defaults. The changes take place immediately, there was no need to restart the servers or replication agreements.
To measure how fast replication was going I would go to the remote server and run something like
grep 2008:10:23 logs/access | grep -c MOD
where 10:23 was the previous minute, to count how many MOD operations had come through in one minute.