On Mon, Aug 08, 2016 at 10:19:29AM +0200, Michal Privoznik wrote: > On 08.08.2016 09:33, Patrick PICHON wrote: > > Hello, > > > > > > All my VMs are using LVs created on the host side. > > > > I'm using collectd to monitor some of the ressources of my host as well > > as the libvirt pluging to monitor my VMs. > > > > Collectd has an interesting plugin ( df ) which can monitor the > > filesystem usage. > > > > I would like to use it to monitor the VMs filesytsem usage. > > > > As it is obvious that if I mount the VM filesystem on the host while the > > VM is running, I'm wondering if I could mount it in READONLY without > > expecting any panic/corruption problem. > > > > > > Any advices ? > > I don't think it is a good idea. Mostly because of caching - you > probably won't get consistent results. Moreover, some filesystems (e.g. > ext4) replay journal even if mounted as RO (frankly, I haven't found a > way how to mount ext really RO). I don't know of any filesystem that > would support being mounted multiple times from two different hosts > (except network FS obviously). Yep, mounting the guest FS on the host is practically guaranteed to lead to data loss. Don't even think about trying it. > What you could do is to write small guest agent that will report disk > usage to host (e.g. via virito serial console). FWIW, you can run the libguestfs guest agent inside a running guest and then connect to it using normal libguestfs API Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| _______________________________________________ libvirt-users mailing list libvirt-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvirt-users
