Ceph developers list

Mandell Degerness | 24 May 2012 01:44

write-through cache

I would like to test the effect of using the new write-through cache
on RBD volumes mounted to Openstack VMs.  What, precisely, are the
changes I need to make to the volume XML in order to do so?

-Mandell
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Josh Durgin | 24 May 2012 02:44

Re: write-through cache

On 05/23/2012 04:44 PM, Mandell Degerness wrote:
> I would like to test the effect of using the new write-through cache
> on RBD volumes mounted to Openstack VMs.  What, precisely, are the
> changes I need to make to the volume XML in order to do so?

If your only volumes are rbd, you can append 
:rbd_cache=true:rbd_cache_max_dirty=0 to the image name in the volume 
xml, so it would include something like

<source protocol="rbd" 
name="pool/image:rbd_cache=true:rbd_cache_max_dirty=0">

Josh
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