Efficiency of searching files in a directory?

Question

I am building a website with a user authentication system allowing each user to upload images to their account, essentially I am doing this as an experience in web development so please forgive my ignorance on the topic.

My question involves the efficiency of placing files into a directory. Is it more efficient to create a deeper directory structure or to place all files into one folder? The former seems obvious, but does it not depend on the search algorithm implemented by the file system?

For example:

root/user/2012/----------------A/
         /2013/---------- A/   B/
         /2014/------A/   B/   C/
                     B/   C/   D/
                     C/   D/
                     D/

Or dump all files into a single folder?

root/user/

When an image is retrieved, for example by an <img> tag, which way provides a more efficient result? I have searched Google for information on the topic, but couldn't find anything definitive or at my level of understanding.

Answer 1

Accessing a single file should be roughly equivalent. A single directory or multiple choice really depends on how you are trying to use the file listing. If you expect the user to have thousands of files and you only display a single year at a time, it may make sense to break up the directory structure into multiple sections to keep file listings manageable. If you always show all the files, I suspect the single folder may be faster, since you will have to run through the whole directory listing doing multiple file listings. I would do a few tests based on what you expect your app to have to deal with. My guess would be a single directory should be fine, unless you expect large numbers of files and you can break the listing down.

Answer 2

i dont know what OS you intend to run on, but i'd go with the multiple directories approach as some FSs (NTFS on windows, for example) slow down horribly when dealing with 10000+ files in a single directory