What mail server are you running?
I'd like to know what kinds of mail servers people are running on *nix boxes. I have had an old mail server running Exim delivery to local mbox format in user's home folders and imapd for client connections.
My new server (which a nice young lady set up for me) is running Postfix with a DBmail backend on MySQL, using dbmail to supply the imap daemon for the clients and putting it through dspam and clamav, which annoyingly changes the subjects of the emails with [SPAM] (especially annoying if they're not spam and then you're stuck with marked emails) but anyway, I may change this later...
I am a little concerned that this setup may blow up some time in the not too far future. I've already seen an alert from my monitoring server that MySQL has too many connections. I can increase this no doubt, but I just don't have all that much faith in the scalability and reliability of this server like I do with say Exchange which I had in my previous workplace.
It already consumes over twice the storage space of the old server (Exim/mbox) and I have had one or two minor issues with it already. It feels like there are too many things that can go wrong with it and if any of them break then the whole thing breaks.
I am very interested in other people's experiences with mail servers so I have something to compare to. Could you please share your experiences; which mail servers you have run in what configs with what users?