[ovirt-devel] Snapshots & clone support from datastore

[Nir Soffer]

On Thu, Jun 22, 2017 at 3:39 PM Yaniv Lavi (Dary) <ylavi at redhat.com> wrote:

> Hi,
> You can have a look at the libfgapi patches as the are the first to
> externalize the snapshot process to separate implementation.
>

Snapshots in libgfapi are not using any external process. The only
difference
is modifying the volume from file path
(/rhev/data-center/mnt/server:path/sd_id/images/img_id/vol_id) to gluster
path
(volume/sd_id/images/img_id/vol_id).

This modification is done when we prepare a volume. This is basically a hack
since gluster connections are not managed properly in engine like other
types
of storage.

Nir


>
>
> Thanks,
>
> YANIV LAVI (YANIV DARY)
>
> SENIOR TECHNICAL PRODUCT MANAGER
>
> Red Hat Israel Ltd. <https://www.redhat.com/>
>
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>
> On Wed, Jun 21, 2017 at 11:57 PM, Deepak Jagtap <deepak.jagtap at maxta.com>
> wrote:
>
>> Thanks Yaniv!
>> ------------------------------
>> *From:* Yaniv Kaul <ykaul at redhat.com>
>> *Sent:* Wednesday, June 21, 2017 1:47:26 PM
>> *To:* Deepak Jagtap
>> *Cc:* Allon Mureinik; devel at ovirt.org
>>
>> *Subject:* Re: [ovirt-devel] Snapshots & clone support from datastore
>>
>>
>>
>> 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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>>>
>>
>>
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