Re: sender rewrining advice

According to mailstats, my server has been averaging 15.5 k messages a day for the last month (10k min and 19k max).  I'm on a small Linode w/ 2 GB of memory.  --  This really doesn't make an impact and it's not like it's a big system.
 

That is good to hear. I am not processing that much yet, but looking forward in doing so.
If you like stats, maybe have a look at mailfromd as a milter. I asked them (Sergey) to add exporter for prometheus, which they did after a year. Now you can practically log now anything you want.