Highly Customized Cs-Cart Multivendor Instance Backup

We have highly customized CS-Cart Multivendor Instance. We're planning to do a backup before launching.

The question is whether there's a possiblity of current instance of CS-Cart crashing due to the backup that we want to start?

How likely it is and is there a possibility of all our customization resetting to default CS-Cart state?

If it is likely then what would be correct to do and is there a way to ensure smooth backup process so that current instance remains intact?