Hi,
We are trying and planning to implement a sharepoint 2019 farm which supports ZDP.
I have read these articles and watched the entire video.
https://docs.microsoft.com/en-us/sharepoint/upgrade-and-update/sharepoint-server-2016-zero-downtime-patching-steps
https://docs.microsoft.com/en-us/sharepoint/upgrade-and-update/video-demo-of-zero-downtime-patching-in-sharepoint-server-2016
The main question is the "simpleness" behind the instruction "Take the webfront out of the load balancer".
Our loadbalancer is BIGIP from F5. The settings there is that if you currently have a connection with the front end, the load balancer doesn't kill/migrate/transition/drain your session. You get to keep it even though the webfront (node) is out of rotation. This has X seconds of timeout so it doesn't take much for you to hop on over to the next webfront but there are scenarios where users are so active that they will keep the session with the front end that is about to be patched.
I have tried this my self and I eventuelly run into the error message "503 service unavailable". I refresh the page for 3-5 seconds and I now I have jumped over to the other web front.
The question is: Is it really zero downtime patching or short downtime patching?
Do you have any recommendations for settings in a load balancer? Surely they are not all the same. Perhaps some settings are unnecessary if Sharepoint deal with some issues that occur when trying to patch with zero downtime?