Thats certainly a logical extension to the system, but orthogonal to fixing a bad default IMO. Admins can already configure a filesystem per OS. -Rob On 20 December 2013 23:00, Daniel P. Berrange <berrange at redhat.com> wrote: > On Fri, Dec 20, 2013 at 09:21:54AM +1300, Robert Collins wrote: >> The default ephemeral filesystem in Nova is ext3 (for Linux). However >> ext3 is IMNSHO a pretty poor choice given ext4's existence. I can >> totally accept that other fs's like xfs might be contentious - but is >> there any reason not to make ext4 the default? >> >> I'm not aware of any distro that doesn't have ext4 support - even RHEL >> defaults to ext4 in RHEL5. >> >> The reason I'm raising this is that making a 1TB ext3 ephemeral volume >> does (way) over 5GB of writes due to zeroing all the inode tables, but >> an ext4 one does less than 1% of the IO - 14m vs 7seconds in my brief >> testing. (We were investigating why baremetal deploys were slow :)). > > I've no objection to changing the default in this way. I would suggest > though that we make the hoice of emphemeral filesystem configurable > per-instance. I can well imagine people wanting to be able to choose > xfs or btrfs instead of ext4. > > My suggestion would be to support a glance image metadata property to > let users specify the filesystem that is suitable for use with their > image. > > 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 > OpenStack-dev at lists.openstack.org > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev -- Robert Collins <rbtcollins at hp.com> Distinguished Technologist HP Converged Cloud