> And the opposite question, can memory balloon be deallocated?? And is > it possible to do this automatically or is an error to do this?? I think your understanding of ballooning may be backwards. The purpose of the balloon driver is to give the host system a way of recovering memory from the guest when the demands on the host's physical memory exceed the amount available. The balloon inflates within the guests forcing them to swap or take other memory management measures. When the pressure on the host eases the balloon deflates automatically. -- Drew "Nothing in life is to be feared. It is only to be understood." --Marie Curie