Postfix is a free and open-source MTA (mail transfer agent) used for email routing. When emails are sent, they are placed into a delivery queue and sent to the destination. On occasions where postfix cannot deliver/forward email, they will be placed into the deferred queue. This article outlines how to flush the queues - flushing will ask postfix to attempt to re-send emails struck in the queue. Please note that you must be logged in as root to see the email queue and to run postfix commands.

In my previous post, I described how to install the proxmox backup client and how to create an account within PBS (Proxmox Backup Server) to allow backup and restore operations on a specific PBS datastore. As well as create a manual backup of a TrueNAS Scale datastore. For a once off backup it would suffice but I wanted a regular backup of my TrueNAS datasets onto the PBS, with logging for trouble shooting if the need arises.