To add another data point: After working with ES for the past 10 years in production I have to say that ES is never giving us any headaches. We've had issues with ScyllaDB, Redis etc. but ES is just chugging along and just works.
The one issue I remember is: On ES 5 we once had an issue early on where it regularly went down, turns out that some _very long_ input was being passed into the search by some scraper and killed the cluster.
The one issue I remember is: On ES 5 we once had an issue early on where it regularly went down, turns out that some _very long_ input was being passed into the search by some scraper and killed the cluster.