expanding vm ware virtual disk that has exchnage 2010 installed on it?

I have a 100gb partition where Exchange 2010 is installed and my free disk space got down to less that 4gb and we stopped receiving external emails.  I was able to delete an old test db that was no longer being used to free up another 3gb which got emails temporarily flowing for now.  However, I know I need another permanent solution to resolve the issue.  My first thought was to just expand the virtual disk as I have some additional storage space available to me with my data center vendor.  My question is:  Is it safe to just expand the virtual disk that contains Exchange or am I at risk of causing some serious problems?  Does anyone have any other suggestions?  I know I could ask users to cleanup some emails by exporting older emails to PST files, but really want to try and avoid that if I can.

Thanks.