On Mon, Apr 30, 2018 at 08:42:56PM +0200, Gionatan Danti wrote: > Another question: how reliable are qcow2 ver2/3 files nowadays? Are you > using them in production environments? qcow2 is widely used in production at large scale in general. Just not with internal snapshots - almost everything uses external snapshots, aka backing file chains. > At the moment, I am using RAW files and filesystem-level snapshot to manage > versioning; however, as virt-manager has direct support for managing qcow2 > internal snapshots, it would be easier to deploy qcow2 disks. > > What strikes me is that, if thing have not changed, Red Hat support policy > was to *not* support internal snapshots. So, are they reliable enough for > production VMs? The QEMU community still tends to discourage use of internal snapshots. There are not even any QMP monitor commands to use them - you are forced to use the legacy HMP interface to QEMU for mgmt. All of the workaround providing interesting block storage mgmt is focused on external snapshots (aka the backing_file option). There are some technical downsides to internal snapshots IIUC, such as inability to free the space used by the internal snapshot when it is deleted, loading/saving snapshots blocks execution of the guest OS, and probably more I've forgotten about. The only nice thing about internal snapshots is simplicity of mgmt, and that is a very nice thing indeed, which is why virt-manager has code to support that - it was much easier to add that code for external snapshots. Just a shame about all the downsides :-( Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| _______________________________________________ libvirt-users mailing list libvirt-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvirt-users
