If you expect to have any folders with lots of messages, I would use mdbox rather than Maildir. NFS tends to have performance problems with lots of small files, and Maildir uses one file per message, where mdbox has a sort of compromise between lots of files and the huge files that mbox creates.
Thanks Patrick.
OK. back to zero again. Now this is new piece of information for me which tell me that mdbox is better than Maildir format for emails on NFS.
Question: Which is best format to go with in general, maildir or mdbox? . We really don't want users to use their NFS HOME directories for storing and accessing their emails. Even if they create any imap folder that should also get created on email server's local storage either in Maildir format or the new format mdbox which I've just heard about.