Unfortunately, I don't think there is a good answer to this unless you had created a snapshot of the clone before you made any modifications. The problem is that 'rbd diff' will always include the parent image diffs (as you've discovered) unless a snapshot is specified.
The forthcoming infernalis release includes a new "rbd disk-usage <image-spec>" command which will accomplish what you desire. It rounds up per-object usage to the full object size for speed, which is probably a closer representation of actual OSD disk usage anyway. If you are feeling experimental, you could install the infernalis-based rbd tools from the Ceph gitbuilder [1] into a sandbox environment and use the tool against your pre-infernalis cluster. [1] http://ceph.com/gitbuilder.cgi -- Jason Dillaman ----- Original Message ----- > From: "Corin Langosch" <[email protected]> > To: [email protected] > Sent: Friday, October 9, 2015 4:42:50 AM > Subject: [ceph-users] how to get cow usage of a clone > > Hi, > > to get the real usage of an image I can run: > > rbd diff image1 | awk '{ SUM += $2 } END { print SUM/1024/1024 " MB" }' > > To get the cow usage of a snapshot: > > rbd diff image1 --from-snap snap1 | awk '{ SUM += $2 } END { print > SUM/1024/1024 " MB" }' > > But I wonder how I can get the cow usage of a clone? I tried passing an > absolute snapshot name "image1@snap1" but that > doesn't work. > > rbd diff clone1 --from-snap image1@snap1 | awk '{ SUM += $2 } END { print > SUM/1024/1024 " MB" }' > rbd: diff error: (2) No such file or directory > > Thanks for any help. > > Corin > _______________________________________________ > ceph-users mailing list > [email protected] > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > _______________________________________________ ceph-users mailing list [email protected] http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
