When throwing more hardware into your Elasticsearch cluster doesn't help and your management tells you that this year the search traffic in our eCommerce site will triple. In this talk, I will present several not-so-obvious Elasticsearch performance issues and provide some proven recipes on how to prevent/fix them. Also, I'll share bits of the infrastructure of our search stack that empowered the team to experiment fast without impacting the production and scale Elasticsearch to handle 1M+ RPMs.