Re: [Engine-devel] Clone VM from snapshot feature
On 02/14/2012 11:03 AM, Yaniv Kaul wrote:
On 02/14/2012 10:53 AM, Yair Zaslavsky wrote:
> On 02/14/2012 10:35 AM, Yair Zaslavsky wrote:
>> On 02/14/2012 10:29 AM, Yaniv Kaul wrote:
>>> On 02/14/2012 10:06 AM, Yair Zaslavsky wrote:
>>>> Hi all,
>>>> I modified the Wiki pages of this feature:
>>>>
>>>> http://www.ovirt.org/wiki/Features/CloneVmFromSnapshot
>>>>
>>>> http://www.ovirt.org/wiki/Features/DetailedCloneVmFromSnapshot
>>> - Missing error handling. I hope all will goes well, of course.
> Will be added. Not sure though what can we do in case for example you
> fail to copy image N out of M , besides of course
Since it's not clear that if you merge the snapshots regardless of the
base image (if it's RAW), or you merge them all to one big image, I'm
not sure if there are two processes here or not - I assume there are:
copy and merge. Each can fail independently, and rollback is probably
required?
>>> - Will you be copying the disks in parallel, or serially?
> CopyImage is an asycnrhonous verb that will be monitored by the
> AsyncTaskManager at Engine core.
Which means that if there are N disks you copy them in parallel or one
by one? May make sense to do it depending on the storage domain - if
it's the same for all or not, etc. An optimization, I guess.
This engine core
code that is required to launch VDS command + create a
task for monitoring it takes less time than completion of the monitoring
itself - so the part of lauch VDS command + create task for monitoring
is serial, but the monitoring itself is performed periodically,
according to the behavior of AsyncTaskManager.
Engine-core is indifferent to whether the copies are performed
concurrently or not in VDSM.
>
>>> - Too bad the disks have to be copied by the SPM. Not sure why, really.
>> Typo, will be fixed.
>>> Same for the merge, which is not really mentioned where/how it's going
>>> to take place (VDSM-wise).
> The copy operation will perform collapse on destination.
> Maybe I do not understand your question here- please elaborate.
Will the merge of the snapshots be done by SPM or HSM?
>
>>> - If the 'Disk1' , 'Disk2' are RAW, would be nice to have an
option NOT
>>> to copy them. Especially as you have a snapshot on top of them.
> Please elaborate on that.
If you are going to merge snapshots into the base, not sure it needs to
be copied first - I wonder if there's an option to collapse to a new
destination. QEMU feature, I guess.
Y.
>>> Y.
>>>
>>>> Comments are more than welcome
>>>>
>>>> Kind regards,
>>>> Yair
>>>>
>>>>
>>>>
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