Nginx is used as a disk cache and varnish is used as a memory cache. So you're saying that why not scrap nginx and let varnish run the show on the edge nodes? T

Nginx is used as a disk cache and varnish is used as a memory cache. So you're saying that why not scrap nginx and let varnish run the show on the edge nodes? That works just fine too. Keep in mind that the goal of the article is to build an affordable CDN based on VM edge nodes. Memory is still expensive on VMs (especially if you're going to be renting VMs in costly locations). So if you have say a 20GB static store that needs to be served, on a 2GB RAM VPS, Varnish will only be able to cache that much files and be forced to make round trips to the dynamic node on miss. Varnish does have "persistent" storage capabilities but from what I've read they're still experimental. Regards