The impact of a high directory-to-file ratio on XFS

Solution 1:

No major recommendations other than that XFS should scale to this. I started using the filesystem in 2003 because I needed to work around an application that could easily have 800,000 files in a single directory. ext2 and ext3 would routinely fall over in operations within those filesystems.

A lot of this depends on your application and how it accesses files (directory traversal, etc.).

If this is all on one server, I would look at external SSD journals based on your expectation of a high number of metadata operations. But you know that part. I would still push for the restructuring using the second md5 example. I mean, this is a good time to refactor, right?