deoren:
> Hi all,
>
> We've been using Postfix for years with good results, but in recent
> years have moved to a load-balanced HAProxy front-end with multiple
> backend relay nodes. I've consulted various sources during that time to
> perform the initial setup and light tuning since then.
>
> The health checks are run often and simulate a full email delivery
> session in an attempt to exercise the full configuration (including
> alias resolution and other related db queries).
>
> This setup works pretty well, but occasionally there is enough of a
> delay between one of the steps in the simulated delivery that the health
> check fails and the node is marked as down.
>
> When this occurs I have been unable to determine exactly why the issue
> occurs. I've adjusted various timeout and timing settings within HAProxy
> and Postfix, so I assume that our mostly stock MariaDB 10.0.x
> installation is likely to blame.
Have you looked in Postfix LOGs? For example, if there is a delay
from the start of the probe to the first Postfix logfile record,
then that would indicate a delay with looking up the client hostname,
and then the address for that hostname.
If there is a hiccup with MySQL, then you might see a Postfix warning
around that time.
etc. etc.
Wietse
> Do you have any recommendations for guides that cover tuning Postfix and
> MySQL? I'd like to start there and work through the steps before turning
> back to the configuration as a whole.
>
> Another option I'm considering is replicating the database contents
> (where applicable) in MySQL to local SQLite databases that are synced to
> the relay nodes, cutting MySQL/MariaDB out of the picture entirely.
>
> Our client node count is currently less than 100.
>
> Thanks in advance for any guides that you can reference!
>
