Varnish Capacity Planning and Hardware Sizing

Question

we want to run a new varnish node to cache video segments "average object size 3MB" and wondering if there is a way to measure the hardware specs "CPU/Memory/Disk" required based on the user's concurrency so we can choose the suitable servers specs

Answer 1

As always, the best way is to test it: install Varnish on a test server and throw some synthetic traffic at it, then monitor the situation and see how it does.

The main issue I'd be worried about is RAM, since Varnish needs to hold on to cached objects. You can specify that Varnish use file storage, but in my experience, large cached files will still consume a large chunk of available memory; I've even had it run the machine into a deadlock.

You should also look into Varnish's streaming support via beresp.do_stream.