I recently installed a media sharing app to one of my servers. It was simple to install, but it hid a dastardly trap for long-term maintenance. Every time a user uploaded a file, the web app saved it to the local filesystem. If I ever blew away the server and rebuilt it, I’d have to backup and restore every file manually. The better architecture would be for the app to write its files to a separate storage server, but I didn’t want to spend months rewriting the app to make that possible.