I am running an nginx webserver serving php files with FPM.
Normally it works super well and fast, but sometimes though there are periods where all page loads will hang and return 504 Gateway Time-out errors. I just wait and this situation will resolve in about a minute or so. %CPU usage on my server (linode) never goes above 5%.
What could be causing this? I am guessing perhaps like a max connections setting or something in php, but am totally lost.