Last night I was up until 6AM doing reboots and backups. It is not
unusual for NFS mount points to not mount or NIS to not bind after a reboot.  Those are bugs I am used to and always check for.

But postfix not starting is unusual, I didn’t check, didn’t notice,
went to sleep and so it didn’t get fixed until someone called around 2PM.

I’ll work on some sort of automated monitoring solution.