What happens if PDM server runs out of memory space

I am wondering what happens in this scenario. It is just a matter of time I am going to see this at my company.
Is there a possibility that vault data can go corrupt because of this event. What is the worst that can happen?
As far as I can tell, our back up system is questionable as it has failed in the past to restore all files from deleted folders (not of the pdm vault). Of course IT says back up system has no problem.
SolidworksWorkgroup Pdm