[Openstack] Large volume creation takes long time

John Griffith john.griffith at solidfire.com
Fri May 23 15:21:07 UTC 2014


On Thu, May 22, 2014 at 11:33 PM, Ruzicka, Marek <marek.ruzicka at t-systems.sk
> wrote:

> Can’t help you here… I’m still running Grizzly, and volume resize came in
> IceHouse I believe.
>
>
>
> Marek
>
>
>
>
>
> *From:* Udara Liyanage [mailto:udaraliyanage at gmail.com]
> *Sent:* 23. mája 2014 07:28
> *To:* Ruzicka, Marek
> *Cc:* openstack at lists.openstack.org
> *Subject:* Re: [Openstack] Large volume creation takes long time
>
>
>
> HI marek,
>
> Thanks for the reply.
> By the way how to resize a volume to zero. I found "cinder extend" command
> where volumes can be extended. How to shrink the volume to zero?
>
>
>
> On Fri, May 23, 2014 at 10:52 AM, <marek.ruzicka at t-systems.sk> wrote:
>
> I’m not 100% sure, but I remember (depending on the driver you are using)
> it used to zero entire volume before deletion, which might or might not
> make sense for you.
>
> Sorry for not being able to provide any details, this is just something I
> remember from way back.
>
>
>
> Cheers,
>
> Marek
>
>
>
> *From:* Udara Liyanage [mailto:udaraliyanage at gmail.com]
> *Sent:* 23. mája 2014 07:00
> *To:* openstack at lists.openstack.org
> *Subject:* [Openstack] Large volume creation takes long time
>
>
>
> Hi,
>
> When it tries to delete a large sized volume, it takes a long time. Is
> there a another better way to do  this such as resizing a volume to zero.
>
>
> --
>
> Udara S.S Liyanage.
> Software Engineer at WSO2.
> Commiter and PPMC Member of Apache Stratos.
> Blog - http://udaraliyanage.wordpress.com
>
> phone: +94 71 443 6897
>
>
>
>
> --
>
> Udara S.S Liyanage.
> Software Engineer at WSO2.
> Commiter and PPMC Member of Apache Stratos.
> Blog - http://udaraliyanage.wordpress.com
>
> phone: +94 71 443 6897
>
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>
> ​The writing zeros to the volume on delete is indeed what you're seeing,
it's a "feature" that is there for security purposes, so for example a
public provider doesn't hand out a new volume to a tenant with the
possibility of allocating blocks with somebody elses data on them.

You can switch to using "lvm_type=thin" in your cinder.conf file which will
basically handle this by returning zero for blocks that haven't been
written yet (so we don't do the secure delete).  Or as was suggested if you
don't need the secure delete option you can turn it off altogether by
setting "volume_clear=none" in your cinder.conf file.

As far as adjusting the size to zero, we don't allow reducing the volume
size, only extending.  Reducing introduces quite a bit of risk and also it
doesn't address the problem that secure_delete is there for anyway.

Thanks,
John​
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