On Wed, 2007-11-21 at 20:29 +0000, Adrian Barker wrote:
Two weeks ago we switched all our IMAP users (around 25,000) from the Washington IMAP server to Dovecot, and since then there have been several occasions when reading new email just hangs, and duplicate emails appear. We are using the 'snarf' plugin to copy new email to the inbox, and it looks as though the problems are caused by file locking.
How do you deliver mails to the mboxes? If not using Dovecot's deliver, the mbox locking order could be different between them and they'd deadlock. mbox_read/write_locks settings affect this.
We have been using the Washington IMAP server for a number of years without any file locking problems, so the underlying file locking mechanism is robust.
Did UW-IMAP really use fcntl locks with mboxes? Could it be that it just didn't, and now the problem is with fcntl locking in general?