In addition to what RHD said you should expect that there will be a performance penalty for running in a virtualized environment. That penalty may, or may not, be a problem for you. It is a trade-off vs the benefits of virtualization. If the benefits are sufficient to justify the performance hit (or the performance hit is small enough to not matter) then it is worth it. Otherwise you shouldn't virtualize.
One of the big drivers of virtualization is to share common resources. As it does in so many other cases this often leads the unwary to implement RAID5 disks. Sometimes without knowing that it is happening. If your environment is at all performance sensitive you do not want to do this. Progress (and by extension QAD's) configuration requirements are not different in a virtualized environment. The basic CPU, RAM, disk and network capacity needs don't magically become any less.