Michael Meier:
> hi all
>
> I've noticed that for sending big mails (10MB) it can take up to 30 min
> until they are sent. So I investigated a bit into the problem. I
> deactivated amavis and dkim, so they do not seem to be part of the problem.
> What happens is, that as soon as I write a bigger e-mail, the system
> load goes up from 0 to around 2.5 and when the mail is send, goes back
> to 0 again, but there is almost no cpu usage at all. So it should have
> something to do with the I/O system I guess.
> iotop tells me that cleanup is writing at around incredible 60 kb/s to
> the disk.
> All other processes work perfectly and don't get slowed down while the
> mail is send, I can even copy to the same partition at normal speed. It
> is just cleanup which seems to be so slow. There is also still enough
> memory left. Besides the speed, email delivery works perfectly, there
> are also no log messages indicating anything.
> I don't think it has to do with the network card since I also tried out
>
> smtp-source -t crap@localhost -l 102400000 127.0.0.1
Completes in a 1-3 seconds on a laptop (ssd) and old workstation
(rust). Obviously the problem is outside of Postfix.
Maybe the outpout from 'lsattr /var/spool/postfix' will reveal
special configuration (sync writes, or something else).
Wietse
> and it shows the exact same behaviour.
> Anybody has any idea what the problem might be?
> I'm using postfix 2.11.3-1 on a debian jessie (stable) with kernel
> 4.9.0-0-686-pae.
>
> thanks in advance
> michael
>
