Comments 1 Posted In Red Hat Virtualization Tags rhev virtio Offline resize a virtio disk for Windows guest in RHEV 3.2 Latest response 2014-11-06T21:13:34+00:00 I have a VM with guest Windows Server, the virtual disk is virtIO PREALLOCATED allocation policy. Is it possible to resize virtual disk? Thanks AG Started 2014-09-08T20:56:24+00:00 by Alexander Gomez Newbie 5 points Log in to join the conversation Responses Sort By Oldest Sort By Newest DO Red Hat Expert 884 points 6 November 2014 9:13 PM Derrick Ornelas Starting in RHEV 3.3 it is possible to extend the size of a virtual disk. It does not matter if the disk is Preallocated or Thin-provisioned, and the operation can be done online (while the VM is running.) It is not possible at all to reduce the size of a virtual disk at this time.