71 lines
2.2 KiB
Markdown
71 lines
2.2 KiB
Markdown
# Process more emails concurrently
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!!! attention
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Processing more emails concurrently requires more RAM, please make sure you
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have enough RAM to handle them, otherwise ClamAV may exit randomly due to
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no enough memory (for ClamAV).
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Amavisd-new is content filter, it invokes SpamAssassin and ClamAV for
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spam/virus scanning, it also offers additional features like DKIM signing and
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verification.
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In [Amavisd config file](./file.location.html#amavisd), `$max_servers` sets
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the number of concurrent Amavisd processes and it must match the number set
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in `/etc/postfix/master.cf` `maxproc` column for the `smtp-amavis` service.
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Sample settings:
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```
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# Amavisd config file:
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# - on RHEL/CentOS: /etc/amavisd/amavisd.conf
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# - on Debian/Ubuntu: /etc/amavis/conf.d/50-user
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# - on FreeBSD: /usr/local/etc/amavisd.conf
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# - on OpenBSD: /etc/amavisd.conf
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$max_servers = 4;
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```
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```
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# File: /etc/postfix/master.cf
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smtp-amavis unix - - - - 4 smtp
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...
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```
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Both values should be identical for two reasons: If Amavisd offers more
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processes than Postfix will ever use, Amavisd wastes resources. On the other
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hand, if Postfix starts more dedicated transports than amavisd can handle
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simultaneously, e-mail transport will be refused and logged as error.
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If many emails stalled in mail queue (check with command `postqueue -p`), and
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your server has powerful CPU and memory, you can increase the number of
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concurrent Amavisd processes, so that it can process more emails at the same
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time. Sample setting:
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```
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# File: /etc/amavisd/amavisd.conf
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$max_servers = 10;
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```
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Restarting Amavisd service is required.
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```
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# File: /etc/postfix/master.cf
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smtp-amavis unix - - - - 10 smtp
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...
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```
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Note: If you don't want to modify `/etc/postfix/master.cf`, it's ok to set
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`smtp-amavis_destination_concurrency_limit = 10` in `/etc/postfix/main.cf`
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instead.
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Restarting Postfix service is required if you modified `/etc/postfix/master.cf`,
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reloading OR restarting is required if you modified `/etc/postfix/main.cf`.
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References:
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* [Amavisd web site](http://www.amavis.org)
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* [Tuning: Maximum Number of Concurrent Processes](http://www.ijs.si/software/amavisd/README.postfix.html#d0e1231)
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* [Integrating amavisd-new in Postfix](http://www.ijs.si/software/amavisd/README.postfix.html)
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