Well, I'll add a late 2 cents ...
There are (as Howard had mentioned - muc) some directories contained in moodledata whose locations would affect 'speed' of the server (page loads, etc.) IF all of moodledata was moved to an NFS or other storage type server. There are others ... the sessions directory in moodledata as well as the temp directory and it's contents. Where the space is eaten up is filedir and trashdir (the latter if not running cron/task often enough).
With those in mind, I've setup servers where 'filedir' is an alias that points to a mount point that really goes to an NFS server. It's the only 'bottleneck' when it comes to 'speed' then.
Nice thing about that setup ... anytime the current NFS fills up it's easily switched to something even larger and actual 'downtime' could be a matter of minutes.
Food for thought?
'spirit of sharing', Ken
