On Tue, Apr 05, 2016 at 05:38:40PM +0200, Cedric Bosdonnat wrote: > On Tue, 2016-04-05 at 16:16 +0300, Roman Kagan wrote: > > On Tue, Apr 05, 2016 at 03:08:48PM +0200, Cedric Bosdonnat wrote: > > > On Tue, 2016-04-05 at 15:52 +0300, Roman Kagan wrote: > > > > On Tue, Apr 05, 2016 at 01:47:33PM +0200, Cédric Bosdonnat wrote: > > > > > Note that VMDP's block driver pvvxblk depends on the ballooning > > > > > driver > > > > > pvvxbn. > > > > > > > > Can you please elaborate on this? Is the balloon driver *used* > > > > by > > > > the > > > > storage driver so that the latter won't work without the former? > > That's correct. The current design requires that the balloon driver be > loaded. The pvvxblk driver is a single binary that runs on both KVM and > Xen. It determines at runtime which environment it is running on and > acts accordingly. The dependency is required for Xen. This also > creates the dependency for KVM. > > > > > What > > > > will happen if the virtio-balloon device isn't configured in the > > > > VM? > > The balloon driver will not load and hence the block driver will not > load. > > > > It's just that without the virtio balloon driver installed, the > > > virtio > > > block one won't start properly, resulting in the famous 0x7B error. > > > > Does it also require the presence of the balloon device? > > Yes. This the default installation. The only way to remove the > balloon device is to launch the vm by constructing a manually > configured command line.
I don't know what management software you use on top of qemu; in libvirt it's certainly possible to remove a balloon device. > Weather the balloon device is present or not, > the user is able to set the current and maximum memory allocations > differently. If different and the balloon device/driver is not > present, the vm will undoubtedly crash at some point. I see no reason for that, but that's out of scope of this discussion. I got your point. Looks like the patchset to cut down the amount of regedits which I was about to post (I'm finishing testing it on various Windows versions) won't work for you as is because it assumes only single-file no-dependency storage drivers. I'll post it anyway; we'll see if it can be adjusted to cover your case, too. Roman. _______________________________________________ Libguestfs mailing list [email protected] https://www.redhat.com/mailman/listinfo/libguestfs
