On Tue, Mar 04, 2014 at 04:15:03PM +0000, Duncan Thomas wrote: > On 28 November 2013 10:14, Daniel P. Berrange <[email protected]> wrote: > > > For this specific block zero'ing case it occurred to me that it might > > be sufficient to just invoke 'ionice dd' instead of 'dd' and give it > > a lower I/O priority class than normal. > > Excuse the thread necromancy, I've just been searching for thoughts > about this very issue. I've merged a patch that does I/O nice, and it > helps, but it is easy to DoS a volume server by creating and deleting > volumes fast while maintaining a high i/o load... the zeroing never > runs and so you run out of allocatable space.
Oh well, thanks for experimenting with this idea anyway. > I'll take a look at writing something with more controls than dd for > doing the zeroing... Someone already beat you to it.... commit 71946855591a41dcc87ef59656a8a340774eeaf2 Author: Pádraig Brady <[email protected]> Date: Tue Feb 11 11:51:39 2014 +0000 libvirt: support configurable wipe methods for LVM backed instances Provide configurable methods to clear these volumes. The new 'volume_clear' and 'volume_clear_size' options are the same as currently supported by cinder. * nova/virt/libvirt/imagebackend.py: Define the new options. * nova/virt/libvirt/utils.py (clear_logical_volume): Support the new options. Refactor the existing dd method out to _zero_logic_volume(). * nova/tests/virt/libvirt/test_libvirt_utils.py: Add missing test cases for the existing clear_logical_volume code, and for the new code supporting the new clearing methods. * etc/nova/nova.conf.sample: Add the 2 new config descriptions to the [libvirt] section. Change-Id: I5551197f9ec89ae2f9b051696bccdeb1af2c031f Closes-Bug: #889299 this matches equivalent config in cinder. 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 :| _______________________________________________ OpenStack-dev mailing list [email protected] http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
