Virtualmin DIsk Quota Inquiry
 

So few days ago I completely used my virtualmin disk quota and somehow mysql failed so I reinstalled everything. Before I go and repeat that, can I ask what is the danger if I set virtualmin disk quota to unlimited? Can I get away with uploading more files into the server? Will mysql still crash?

You're using Virtualmin on a cloud server, yes?
Perhaps that question would be better directed to your service provider. I'd expect there to be a finite limit to the amount of disk space for which you've contracted.