File system backups or snapshots on SANs or the like will never be able to generate a good backup of a running Progress database. There might be SAN vendors claiming that they can but they don't understand how a database is different than flat files.
The recommended way to backup a Progress database is always to use probkup regardless whether you are doing an online or offline backup. That way it is ensured that the backup containes every relevant database block of every extent which might be spread across different file systems and folder structures.
Nevertheless, Progress allows you to set quiet points on a running database which effectively block any update to the database until they are released. When the quiet pont is set you are able to backup a running database by gathering all necessary files and copy them somewhere else or make snapshots of the relevant file systems. Still, I don't think you will find anybody on this forum that would recommend you to do so.
You should always trust the backup utility of the database vendor - at least when it is a Progress database - more than any other magical thing. probkup has a proven track record and has never failed on me in 25 years. I can not say that about other backup strategies like file system snap shots.
In the end, whatever disaster recovery strategy you implement: Make sure it really holds water by thoroughly testing it and that it fullfills your needs. It ain't fun telling the boss that, by the way, unfortunately, your production system was not covered the way it should have been ...
Heavy Regards, RealHeavyDude.