Recently I'm doing a lot of tests on a machine with very limited hardware, in particular only 4 GB of RAM.
Running Elasticsearch plus Kibana and a couple of Logstash instances, I'm noticing a lot of situations in which Kibana shows me the Elasticsearch timeout (>30000ms).
I think this is a valuable situation to practice with ELK requirements.
However, I'm unaware of what are the reasons why Kibana is so slow. First thing first, Elasticsearch and Kibana are not showing particular errors. Logstash instances are sending data regularly.
Nevertheless, working on Kibana is so slow and I can't understand why. Probably it is not a surprise, the Discover panel is the slowest page.
On our production server the machine has 16 GB of RAM, and I think this helps much. But... How to understand when Elasticsearch is being "pushed to the limit"?
I found some very nice documentation (like https://www.elastic.co/blog/found-sizing-elasticsearch) but I think it would be valuable to discuss and summarize where one shoud look to assess if the performances of Elasticsearch are fine for the hardware specs on which it is running.