I have a 3 nodes cluster with two main indices, 3 shards and 3 replicas each. Each node has total 16GB RAM with 6GB reserved to ES. I see the following pattern.
Memory percent starts at ~14% and in 22/24hs it reaches ~75%. That's when old collection GC kicks in and memory goes down at ~14%.
Suddenly two days ago, one of the nodes (master node) reached ~75% in 12hs instead of the usual 22/24hs. Performance is still superb and the node is super responsive, but I'm just curious as to why this happened. I don't see anything special in the logs, besides scattered infos about GC overhead and seldom any WARN because it reached 500ms+. That's for all nodes.
What I noticed is that usually old collection adds 2/3mb per minute per node, but in this node I see sudden spikes of hundreds of MBs, which makes it deviate a lot from what was so far the standard behavior.
Still performance is great and old collection GC is in the ~300ms time, so it's not a big a deal, but I just want to make sure everything is fine now that indices sizes are not that big (8GB total, 3M docs).
Thanks a lot in advance!