Hi, I'd like to share that I found the solution to my problem in [1]. It was the config option "cache_images" in nova that is set to "all" per default. Despite changing the glance image properties of my images to raw it didn't prevent nova from downloading a local copy to /var/lib/nova/instances/_base. Setting "cache_images = none" disables the nova image cache, and after deleting all cache files in _base a new instance is not flat anymore but a copy-on-write clone like it's supposed to be. Sorry for the noise in this thread. :-) Have a nice weekend! Eugen [1] https://ask.openstack.org/en/question/79843/prefetched-and-cached-images-in-glance/ Zitat von melanie witt <melwittt at gmail.com>: > On Fri, 12 Oct 2018 20:06:04 -0700, Remo Mattei wrote: >> I do not have it handy now but you can verify that the image is >> indeed raw or qcow2 >> >> As soon as I get home I will dig the command and pass it on. I have >> seen where images have extensions thinking it is raw and it is not. > > You could try 'qemu-img info <image>' and get output like this, > notice "file format": > > $ qemu-img info test.vmdk > (VMDK) image open: flags=0x2 filename=test.vmdk > image: test.vmdk > file format: vmdk > virtual size: 20M (20971520 bytes) > disk size: 17M > > [1] https://en.wikibooks.org/wiki/QEMU/Images#Getting_information > > -melanie > > > > > _______________________________________________ > Mailing list: http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack > Post to : openstack at lists.openstack.org > Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack