[one-users] OpenNebula ceph snapshots problem.

Javier Fontan jfontan at opennebula.org
Wed Apr 30 03:41:23 PDT 2014


I'm not sure I follow you with that. Just changing the TM from ceph to
qcow2 is something that probably doesn't work. One of the things that
can be failing is that getting the free space from ceph and qcow2 is
totally different and it may be that the datastore is reporting 0
bytes free. In this case the scheduler will never start a VM that uses
that datastore.

On Wed, Apr 23, 2014 at 9:18 AM, Leszek Master <keksior at gmail.com> wrote:
> I tried to change rbd image version from 1 to 2 but it doesn't work. But
> when i changed in my ceph datastore TM_MAD to qcow2 the new VM instantized
> from image that was in the datastore stuck on "PENDING". Is there any way to
> get this working with "existing" images?
>
>
> 2014-04-21 14:53 GMT+02:00 Stuart Longland <stuartl at vrt.com.au>:
>
>> On 17/04/14 01:18, Leszek Master wrote:
>> > 1) I'm using OpenNebula 4.4 with ceph datastore. When i try to make
>> > snapshot i've got error:
>> > 3) Is there any way to use copy-on-write in opennebula 4.4 ?
>>
>> I did some experimental work on this with our OpenNebula 4.4 instance.
>> It relies on modern kernel's ability to map version-2 RBD images using
>> the kernel rbd driver, so it needs kernel >3.10 (? Not sure of exact
>> version; we're using 3.13).
>>
>> This newer format allows copy-on-write cloning.  "Hot" snapshots work,
>> however I haven't managed to trigger a deferred snapshot, so that's
>> untested.  The driver also makes use of hypervisor-side cache using
>> FlashCache, allocating slices of a nominated LVM volume to boost
>> performance.
>>
>> I've thrown my work into a git repository for now, consider this very
>> much pre-alpha.  If you're brave, feel free to give it a go:
>>
>> git clone git://git.longlandclan.yi.org/opennebula-ceph-flashcache.git
>>
>> Regards,
>> --
>> Stuart Longland
>> Systems Engineer
>>      _ ___
>> \  /|_) |                           T: +61 7 3535 9619
>>  \/ | \ |     38b Douglas Street    F: +61 7 3535 9699
>>    SYSTEMS    Milton QLD 4064       http://www.vrt.com.au
>>
>>
>
>
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-- 
Javier Fontán Muiños
Developer
OpenNebula - The Open Source Toolkit for Data Center Virtualization
www.OpenNebula.org | @OpenNebula | github.com/jfontan



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