[ovirt-devel] Snapshots & clone support from datastore

[Yaniv Kaul]

On Wed, Jun 21, 2017 at 10:28 PM, Deepak Jagtap <deepak.jagtap at maxta.com>
wrote:

> Hi Allon,
>
>
> I am trying to leverage snapshot  capability of underlying filesystem.
>
> As per my understanding current snapshot works like this:
>
> Base Image(raw)--->snap1(qcow)->snap2(qcow), i.e after each snapshot vm
> starts writing on newly created qcow image.
>
> So in this case vm is going to do all new writes on snap2(qcow) voulme and
> will redirect read IOs to snap1 & Base image as required.
>
>
> But in my case snapshots created by the filesystem are read only and it's
> in raw format.
>
> As a result after creating snapshot vm disk configuration won't change
> after taking snapshot but will continue doing writes on same base image.
>
> So snapshots will look like this:
>
> Base Image(raw)--->snap1(raw)->snap2(raw)
>
> Base Image will always remain writable, while the snapshots will remain
> read only raw format.
>
>
> Just wanted to confirm is this configurable so that vm continues
>  referring base image after the snapshot instead of newly created qcow
> image?
>

It is not. It'll need code modification to allow externally taking
snapshots of VM disks.
Y.


>
> Thanks & Regards,
>
> Deepak
>
>
>
>
>
> ------------------------------
> *From:* Allon Mureinik <amureini at redhat.com>
> *Sent:* Tuesday, June 20, 2017 7:59:03 PM
>
> *To:* Deepak Jagtap
> *Cc:* devel at ovirt.org
> *Subject:* Re: [ovirt-devel] Snapshots & clone support from datastore
>
> Not sure I understand the question. Could you give an example of what you
> mean perhpas?
>
> On Tue, Jun 20, 2017 at 10:01 PM, Deepak Jagtap <deepak.jagtap at maxta.com>
> wrote:
>
>> Hi Allon,
>>
>>
>> After going through current vdsm code base, noticed that after taking a
>> snapshot vm starts referring the newly created qcow image/volume.
>>
>> For internal snapshots which are not qcow  is it configurable somehow so
>> that vm continues doing writes to same base image?
>>
>>
>> Thanks & Regards,
>>
>> Deepak
>> ------------------------------
>> *From:* Deepak Jagtap
>> *Sent:* Tuesday, June 6, 2017 3:37:03 PM
>> *To:* Allon Mureinik
>> *Cc:* devel at ovirt.org
>> *Subject:* Re: [ovirt-devel] Snapshots & clone support from datastore
>>
>>
>> Thanks Allon!
>>
>>
>> Best Regards,
>>
>> Deepak
>> ------------------------------
>> *From:* Allon Mureinik <amureini at redhat.com>
>> *Sent:* Tuesday, June 6, 2017 2:43:17 PM
>> *To:* Deepak Jagtap
>> *Cc:* devel at ovirt.org
>> *Subject:* Re: [ovirt-devel] Snapshots & clone support from datastore
>>
>> Unfortunately, there's no such integration point at the moment.
>>
>> On Tue, Jun 6, 2017 at 5:57 AM, Deepak Jagtap <deepak.jagtap at maxta.com>
>> wrote:
>>
>>> Hey Guys,
>>>
>>>
>>> I am newbie to ovirt, and wanted to confirm whats the best way to
>>> leverage snapshot, clone features
>>>
>>> provided by the datastore filesystem.
>>>
>>> I have a btrfs datastore exported and wanted use btrfs snapshots for vm
>>> snapshot & clones.
>>>
>>> Does ovirt offers any hooks/APIs so that image snapshots are created by
>>> the filesystem?
>>>
>>>
>>> Thanks & Regards,
>>>
>>> Deepak
>>>
>>>
>>>
>>> _______________________________________________
>>> Devel mailing list
>>> Devel at ovirt.org
>>> http://lists.ovirt.org/mailman/listinfo/devel
>>>
>>
>>
>
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