On Thu, Dec 05, 2013 at 06:12:22AM -0700, Eric Blake wrote: > On 12/05/2013 04:56 AM, Daniel P. Berrange wrote: > > >>>>> > >>>>> This patch enables percentage limit for ram filesystem > >>>>> > >>>>> <filesystem type='ram'> > >>>>> <source usage='10%'/> > >>>>> <target dir='/mnt'/> > >>>>> </filesystem> > >>>>> > > > > > I just don't see this as a compelling feature. I think it is more important > > to have a single canonical representation of memory allocation. User > > convenience is something for higher level tools to worry about. > > But do higher level tools already have a way to query libvirt what the > current host's available ram is, in order to determine percentages > itself? We can't really migrate online LXC guests, but for an offline > guest setup, copying XML from one host with small memory to another host > with large memory, and still having the guest have a fixed percentage of > the host resources (more memory assigned to the guest on the larger > host), seems like a reasonable desire; to achieve that, the management > tool needs to be able to either request percentages (no change to the > guest xml being copied) or know the host resource limits (and rewrite > the xml rather than merely copy it). We do have APIs for querying host RAM, but if we wanted this, which I don't think we do, then tmpfs RAM % would want to be relative to guest RAM allocation not host RAM. It doesn't make sense to have guest XML whose semantics differ according to the host environment - they should be self-contained. 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 :| -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list