Hi everyone and Happy New Year! I wish you all all the best in 2026!
1-2 months ago we had a situation that in my opinion is worth duscussing with you so we can be aware ond probably avoid for anyone.
Here are some details on what happened and how we resolved it:
We had a JAVA application that was monitored in Dynatrace with the automatic OneAgent JS injection for RUM. At some point there was a change on the load balancer side (NetScaler) and the CSM feature (Client Side Monitoring) was enabled on the LB. This caused the pages of that application to either not load at all or load significantly slower.
As a first resolution we have disabled RUM for this application and everything went back to normal. Then after some troubleshooting and timetracking of what was done in this timeframe we saw the enablement of this CSM feature on NetScaler and decided to disable it instead. So we disabled CSM and re-enabled Dynatrace RUM. Everything was working normally.
So we realized that Netscaler CSM and Dynatrace RUM cannot work in parallel.
I am not sure if this is expected behaviour, if somebody has faced this before and what was the resolution. I would be thankful if someone has some experience and knowledge on the topic and I think it would be beneficial to everyone to have this in the community discussions so we can either have this in mind to avoid it or know how to rectify it if it happens for someone.
Thanks to everyone who will respond!
All the best,
Georgi
Dynatrace Associate | Monitoring Engineer | Product Owner - Observability
