I could see one running out of inodes for a sizable dataset. Also, this seems like it would incur a good deal of iowait opening and closing all those fds.
Yes I guess the btree (or similar) will be much better for many small items, but the file solution may be the way to go for not su much items but much bigger...
Eventually maybe the fs solution can just be removed... it was a way to get started with the caching layer asap.
