Is there a way to pause mail delivery in Postfix (accumulate in queue)?

Question

When using combination of Postfix/Dovecot, is there a way to tell smtp server (Postfix) not to store mails on disk but hold/add them to queue until "maintenance finished"?

Useful for disk upgrades, volume extensions, chkdisk etc.

score 14 · Answer 1 · edited Aug 20 '19 at 08:06

14

Use this to stop (pause) and start delivery of outgoing mail again:

sudo postconf -e defer_transports=smtp; sudo postfix reload
sudo postconf -e defer_transports=; sudo postfix reload; sudo postfix flush

This should be applicable to other transports as well.

Source: nixtips.net

edited Aug 20 '19 at 08:06

bjoster

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answered Aug 19 '19 at 21:17

trogper

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score 3 · Answer 2 · answered Dec 21 '12 at 05:15

3

Just shut down postfix. Any legit sending server will queue your mail and retry after a time delay if it is not able to contact your server. As long as your maintenance is short, say under 6 hours, your chances of losing mail are very small.

answered Dec 21 '12 at 05:15

EEAA

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This could be a good answer but then what to do with internal users who connect to the smtp for outgoing mail? – Alex Dec 21 '12 at 05:54
@Alex During maintenance? – Michael Hampton Dec 21 '12 at 18:20
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@Alex - I agree with Michael here. If you only have a single server, you're clearly not in a high-availability environment to start with, so just take things down during a published maintenance period. This is fairly standard practice, and is typically well-received by users as long as you communicate with them about it. – EEAA Dec 21 '12 at 19:46
The nasty corner case involves things like [ActionMailer](https://guides.rubyonrails.org/action_mailer_basics.html) that need Postfix and send mail that isn't from local users. And really, why should a "forgot my password?" form have its own mail queue? – arnt Jul 12 '19 at 09:11

score 2 · Accepted Answer · answered Dec 21 '12 at 04:41

I don't believe so; the incoming queue is on disk. Perhaps you could temporarily move the queue to a ramdisk mount?

mkdir /mnt/pframqueue
mount -t tmpfs -o size=512M tmpfs /mnt/pframqueue
service postfix stop
mv /var/spool/postfix/* /mnt/pframqueue/
<<<adjust 'queue_directory' in main.cf to /mnt/pframqueue>>>
service postfix start

Do the opposite once you're done.

IMHO that's more trouble than it's worth, especially if something goes screwy in the mv

Is there a way to pause mail delivery in Postfix (accumulate in queue)?

3 Answers3