Filesystem structure for website with a large amount of uploads
I'm working on a web project for a client, and it's going to rely heavily on user uploads. The current issue I'm struggling with is how exactly to design the filesystem structure. The reason I'm coming here is to see if there are any downsides to having say.... 50,000 subdirectories under an uploads/ directory? What about 1,000,000? Is there a limit to directories in a linux filesystem? I'm of course going to segment the directories into chunks of x number of uploaded files, but am currently determining what x number is. Any advice on filesystem design if you were creating a youtube/flickr type site that could possibly have millions of uploads?