On Thu, 2020-12-24 at 14:27 -0700, Chris Murphy wrote:
On Thu, Dec 24, 2020 at 4:23 AM Patrick O'Callaghan
<pocallaghan(a)gmail.com> wrote:
>
> The Windows image file is in fact just an fallocated file used as a raw
> disk, not a qcow. It's on an SSD and seems quite fast, so I wouldn't
> worry overmuch about fragmentation. This system is basically only used
> for gaming with GPU passthrough so pretty much everything can be lost.
Latencies are much lower on SSD.
> My interest in snapshotting it is just to avoid the pain of a misconfig
> in QEMU, which is notoriously picky (lomng story short, I'm trying to
> modify it to use a Q35 CPU instead of the basic i440). The VM was set
> up on virt-manager when the filesystem was ext4, so it won't have any
> of the special BTRFS stuff unless I add it myself.
Note that the VM image file contains no VM settings. So a snapshot of
the VM image only helps you preserve/rollback to a previous state of
that image. The image contains only file systems. So if the idea is to
roll back the guest's file system, then you're on the right track. If
the idea is to be able to rever qemu configuration, you want something
else.
Yes, good point.
My advice is to use:
virsh dumpxml $vmname > $vmname.xml
You can then make modifications, and dump that out as a separate name,
and you can diff the xml files.
You can also create a new vm from this exported xml using
virsh create $vmname.xml
Note that the name of the VM is in this file, so if you want to create
a new VM you need to edit the xml file and change the name of the VM
so it gets created with a new name.
Yes.
poc