Good point Christopher! This is a very important note to be aware of.
I think you should stop Smartermail Service, start VSS backup and then start SmarterMail Service without wait the full backup is finished.
The anly part you must wait to be completed is the VSS snapshot BEFORE the backup start the real copy of data, BUT I don't know how to be aware of the completion of the VSS snapshot...
We use Veaam for our backup...
Gabriele Maoret - Head of SysAdmins at SERSIS
Currently manages 6 SmarterMail installations (1 in the cloud for SERSIS which provides services to a few hundred third-party email domains + 5 on-premise for customers who prefer to have their mail server in-house)