All,

I have a new Postfix server that we use to send subscription emails out to customers and send around 200k emails a day. The server is working well, but the queue gets backed up fairly quickly during business hours. In looking at the mailq we have around 20k emails in there and 19k of them are just sitting and waiting to be delivered, where around 1k are deferred to try again later.

In my review of the performance items I am having a hard time determining how to increase just the output parameters. Meaning allow it to process and send more emails at the same time. CPU/RAM and Disk I/O are not the issue as all that looks good. I just need to configure the server to be able to process more outbound emails at a time.

Any assistance is appreciated.

UPDATE... So, up to 90k sitting in the queue today, yet the server seems to be running fine. Can't figure out why it is not getting them sent...

iostat -x

Linux 5.4.17-2011.6.2.el8uek.x86_64 (xxx.xxxxxxx.com) 10/01/2020 x86_64 (1 CPU)