Re: [libvirt] [PATCH 1/3] add percentage limit parse and define support for RAM filesystems

-----Original Message----- From: Daniel P. Berrange [mailto:berrange@redhat.com] Sent: Thursday, December 05, 2013 9:17 PM > > > > 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 :|