Taming the vfs

Found an interesting tool for tracking/controlling the disk cache today - https://hoytech.com/vmtouch/

 Apache listen backlog

tl;dr : ss -lti '( sport = :http )'

I've previously advised that keeping connections in the ListenBacklog is cheaper than keeping them in swap. But until Apache starts refusing connections, there's not much visibility of the state. Today, I found a great article by Ryan Frantz which takes a bit of a deeper dive into how this works and how to measure the usage.