[Openstack-operators] cinder-api with rbd driver ignores ceph.conf

Saverio Proto zioproto at gmail.com
Thu Nov 12 15:25:37 UTC 2015

Hello there,

I am investigating why my cinder is slow deleting volumes.

you might remember my email from few days ago with subject:
"cinder volume_clear=zero makes sense with rbd ?"

so it comes out that volume_clear has nothing to do with the rbd driver.

cinder was not guilty, it was really ceph rbd slow itself to delete big volumes.

I was able to reproduce the slowness just using the rbd client.

I was also able to fix the slowness just using the rbd client :)

This is fixed in ceph hammer release, introducing a new feature.


Enabling the object map feature rbd is now super fast to delete large volumes.

However how I am in trouble with cinder. Looks like my cinder-api
(running juno here) ignores the changes in my ceph.conf file.

cat cinder.conf | grep rbd


But when I create a volume with cinder, The options in ceph.conf are ignored:

cat /etc/ceph/ceph.conf | grep rbd
rbd default format = 2
rbd default features = 13

But the volume:

rbd image 'volume-78ca9968-77e8-4b68-9744-03b25b8068b1':
    size 102400 MB in 25600 objects
    order 22 (4096 kB objects)
    block_name_prefix: rbd_data.533f4356fe034
    format: 2
    features: layering

so my first question is:

does anyone use cinder with rbd driver and object map feature enabled
? Does it work for anyone ?

thank you


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