I'm planning to expand and move to on-premise my ELK Stack. For now, my ELK is built on OpenStack private cloud, and I couldn't improve my stack's performance as I desired.
So, I'm looking for suitable hardware, but I don't know which one will affect to ELK performance most: CPU, RAM or Storage. I want to focus my budget to most performance-related components, so, which one will affect performance most?