Recently enough I was troubleshooting a web performance issue for a customer (spoiler – there were multiple bottlenecks outside of Domino).
One thing I thought I’d highlight, when turning on some debug parameters, Domino began throwing “SSL handshake errors”.
Many of them. As in all the time.
So many that I thought maybe something is up in the Domino Configuration. To be honest, with Domino Cert Manger it’s easy to check and my experience is there just isn’t problems there. I thought maybe there were binding to IP issues on the host.
It took 5 or 6 calls with a Azure admin before it comes to light that the Azure Load Balancer (in front of the two Domino web servers) wasn’t actually polling to check if the actual service was up (i.e. checking a URL https://dominoserver/database.nsf).
It was “just” checking the port status i.e. the port 443 was open. This was the cause of the “SSL Handshake” problem. The good thing is that this highlighted that the load balancer was never configured to work as effectively as it should and was changed to check an actual URL response.
What it goes to show is that even if you think you understand a topology, never assume anything. Particularly when there’s performance issues and multiple moving parts, check configuration, ask questions about exactly how something is configured and verify same if possible. (sometimes people can think something is set up one way and when they check it isn’t).
Technology, regardless of vendor will mostly do what it’s told to do. Often though it’s doing something you don’t want it to!
Cormac McCarthy – Domino People Ltd
