I've got a site with a lot of images and we are currently using apache to serve the static thumbnails. We have over 1.7 million thumbnails using over 30GB of disk space. So the average thumbnail is around 18kb.

I'd like to setup a new dedicated server with 8GB RAM just running nginx to serve the static thumbnails.

What will be the best way to approach the nginx configuration to take advantage of the RAM for caching the most frequently accessed thumbnail images and reducing disk I/O?

Thanks for your help,
James