When backups run the website becomes temporarily unavailable. As I understand it this is due to the services for the “box” being shutdown during the backup process in order to guarantee that a useable backup is created. I on the other hand do not use the builtin backup feature of MiaB. I run this server in a virtualized environment and I am taking backups of the entire virtual machine running. I am not sure if VPS offer this, but I believe it is commonly referred to as a ‘snapshot’. This keeps the box running at all times and relies on VM tools to quiesce the file system.
I have tested my backups and they work fine, however I’m not about to recommend something that is outside the scope of the project and therefore largely unsupported here. It at your own risk (which I guess you could argue so is running your own mail server in general).
I am more curious if your box’s time is correct. I believe the backup script is set to happen at 3AM (specific to the time zone you are in) so unless you have a bunch of people checking mail at 3am then I’m not sure how this is much of a problem.
Maybe @openletter could comment if I am correct with the 3am thought…
Next question would be maybe you set a different time zone on your box?
box$ timedatectl
Should show you everything you need to know from the CLI.