Re: Create qcow2 v3 volumes via libvirt

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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



[Index of Archives]     [Virt Tools]     [Lib OS Info]     [Fedora Users]     [Fedora Desktop]     [Fedora SELinux]     [Yosemite News]     [KDE Users]

  Powered by Linux