On Mon, 27 Aug 2001, Michael Bartlett wrote:
> are about 1300 users on the machine. i don't get that many smtp connections,
> but when i do - they send a LARGE amount of mails to me. so i don't believe
> the performance problem is network related, i believe its filesystem
> related - even though it is a SCSI drive - it may be because of all the file
> locks and concurrent file usage.
Exim hammers file systems. It creates and deletes several files for each
message. Heavy users have always reported that what runs out first is
file access capacity.
> from reading around today, i believe my problem may be the high impact usage
> of the /var/mail/username mboxes. if i look at my exim logs and my cucipop
> logs, i see a LARGE amount of spool file locks, errors opening mail boxes.
> often cucipop is unable to delete mails from the mbox which results in
> recurring mail problems during POP3 pickup.
> i've tried many things, now i believe the way forward is to change my
> configuration from mbox to maildir style.
That's certainly one approach. Another one is to try setting
lock_fcntl_timeout in the appendfile transport. RTFM to see how this
might affect things. It certainly helped one busy site. Something else
that might help, depending on how many mailboxes you have, is to split
them into /var/mail/xxx/username so that they aren't all in the same
directory. Look at ${nhash for a way of computing xxx.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
