[Dovecot] Dovecot-1.0.beta1: New mail sometimes fails to appear

[Tom Alsberg]

Previously I wrote:
> * INBOX in /var/mail/%u
> * most mailboxes in ~/imap.maildir/... as maildirs.
> * mboxes in ~/imap.mbox/... accessible as #imap.mbox/...
> * the mbox:~/mail/ is for when namespaces are not used - now there are 
>   so it should not be relevant

A few related details which are probably highly relevant I forgot to add:

* Dovecot is running on FreeBSD 5.4

* both home directories and /var/mail are on NFS - stored on another 
server (NetApp)
   - This means that the only way to get new mail is to do continuously 
check (poll/busy-wait) whether there are any changes in the mailbox, 
which the IMAP process does.  No epoll/inotify or anything like that.
   - We have and had many different operating systems, and generally the 
situation here is that NFS locking (fcntl/flock) always breaks some way 
or another since we can't get all hosts to work the same way with it, so 
we don't try at all.  All mail accesses (deliveries using Exim, and 
access using all mail clients we have around here) are using dotlocks 
(creating a file with the same name ending with ".lock") to avoid 
concurrency issues.  Dotlocking is configured in dovecot.conf (attached 
in the referred message) as follows:

lock_method     = dotlock
mbox_read_locks         = dotlock
mbox_write_locks        = dotlock
# Timeout to overwrite dotlock files if mailbox isn't modified:
mbox_dotlock_change_timeout     = 30

   -- Tom

-- 
   Tom Alsberg - hacker (being the best description fitting this space)
   Web page:	http://www.cs.huji.ac.il/~alsbergt/
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