[Openstack-operators] cinder volume_clear=zero makes sense with rbd ?

Chris Friesen chris.friesen at windriver.com
Wed Nov 4 16:52:12 UTC 2015

On 11/04/2015 08:46 AM, Saverio Proto wrote:
> Hello there,
> I am using cinder with rbd, and most volumes are created from glance
> images on rbd as well.
> Because of ceph features, these volumes are CoW and only blocks
> different from the original parent image are really written.
> Today I am debugging why in my production system deleting cinder
> volumes gets very slow. Looks like the problem happens only at scale,
> I can't reproduce it on my small test cluster.
> I read all the cinder.conf reference, and I found this default value
> =>   volume_clear=0.
> Is this parameter evaluated when cinder works with rbd ?

I don't think that's actually used with rbd, since as you say Ceph uses CoW 

I believe it's also ignored if you use LVM with thin provisioning.


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