Thanks Keith, That's the detail level I was after. The filesystem running on the NFS server is [btrfs](https://btrfs.wiki.kernel.org/index.php/Main_Page) btw. It occurred to me (after posting, of course) that the NFS tests ought to be running from multiple machines to test it properly, it wasn't, in fact. I'm perfectly happy to trade speed for scale. Unless it's truly glacial in nature, the speed of the filesystem isn't going to the the limiting factor. Reliability of course is a totally different matter.