I haven't seen this specific behaviour in the past but things that I would look at are:
- JVM options which differ between 3.11 defaults and what you have configured in 2.2 - review your monitoring and check read throughput on the upgraded node as compared to 2.2 nodes - possibly not have disk access mode set to map index files only (not directly related to long GC pauses) If you're interested, I've written a post about disk access mode here -- https://community.datastax.com/questions/6947/. Cheers! >
