Brian wrote:
On Mon, May 31, 2004 at 07:24:41PM +0300, Timo Sirainen wrote:
-ERR This message has been deleted by someone else!
or something like that. I can live with that.
That's what Dovecot does now.
But that isn't the worst if you have no locks at all. You still want to lock the mailbox while it's being read or written, otherwise there would be either mailbox corruption (two writers at the same time) or user could be sent corrupted mails (one reading while another is writing).
Oh yes, sorry. I now think "Maildir" exclusively, and forget that some people still use mbox :-)
Converting tens of thousands of users (in a fast and transparent as possible fashion) is no easy feat.
Having seen mailservers where users leave 10-20MB of mail on the server, in a single mbox file, where the POP3 server has to read through the whole mbox every time they login just to count how many messages are in there... well, that's enough for me to give up on mbox.
Tell me about it. ;P
Note though that maildir still leaves you vulnerable to some extent with large individual mails (we allow for 10MB per message max here). The atomic tmp -> new move prevents of course the case of multiple (inbound, SMTP) writers. Alas following a recent conversation in this ML with Timo all that saves your butt and mail integrity in the case when a large message being read by slow client gets deleted by another client (dovecot instance) is Saint BufferCache. ;)
Regards,
Christian
Christian Balzer Network/Systems Engineer NOC chibi@gol.com Global OnLine Japan/Fusion Network Services http://www.gol.com/