> > To avoid high load, reduce the default_process_limit to something > that your VM can handle. I suggest reducing it from the default 100. > > postconf default_process_limit = 10 > postfix reload > > Otherwise you're just running the VM into the ground. Postfix is > an event-driven system, and some VM implementations will lose timer > events and that is what prevents Postfix from working down the queue > without human triggers. >
Yikes - default_process_limit was actually set to 200, I think that was a leftover from the previous installation that was done on a physical host. Thanks for the education! On Wed, Sep 10, 2025 at 9:02 AM Wietse Venema via Postfix-users < postfix-users@postfix.org> wrote: > BuzzSaw Code via Postfix-users: > > We have a mail server running Dovecot (2.3.x) and postfix (3.5.x) on > > RHEL8, using the RPMs from RedHat. Postfix is configured to use the > > Dovecot lmtp for deliveries to the local maildir for each user. > > > > This server uses a virtual user setup, all mail goes under > > /home/vmail/<domain>/<user>/Maildir and the virtual_alias_maps are all > > LDAP based. > > > > We've had a few incidents where we have a large blast of email that > > comes in - usually caused by multiple services and systems all > > reporting a network outage or some other large event. > > > > When that happens, the mail server queue gets backed up, the load on > > the server gets extremely high (30-40), > > To avoid high load, reduce the default_process_limit to something > that your VM can handle. I suggest reducing it from the default 100. > > postconf default_process_limit = 10 > postfix reload > > Otherwise you're just running the VM into the ground. Postfix is > an event-driven system, and some VM implementations will lose timer > events and that is what prevents Postfix from working down the queue > without human triggers. > > > and these errors pop up in the logs: > > > > postfix/qmgr[ZZZZZZ]: warning: mail for foo.bar.com is using up X of Y > > active queue entries > > > > where X > Y e.g 6040 of 3065 and 'foo.bar.com' is the mail server > itself. > > The logging may also suggest to change xxx_destination_concurrencly_limit > or to increase the qmgr_message_active_limit. But that does not > help when almost all your mail is going to the same place. > > Wietse > _______________________________________________ > Postfix-users mailing list -- postfix-users@postfix.org > To unsubscribe send an email to postfix-users-le...@postfix.org >
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