[ovirt-users] oVirt VM backup and restore

[Maton, Brett]

My 2cents

  I think it would be very handy to be able to choose to save the memory
state or not.

  As for anything requiring the memory state depends very much on what your
recovery procedure is.

  Gianluca, PostgreSQL pg_start / end backup works very well.  I can't
remember exactly how it works but it's something along the lines of
stopping (disk) writes to the database and storing change in WAL (redo in
oracle speak) until the backup is complete then applying any changes to the
database files on disk.
  Basically means that the database files won't change during the backup
process.

On 9 March 2017 at 10:57, Gianluca Cecchi <gianluca.cecchi at gmail.com> wrote:

> On Thu, Mar 9, 2017 at 11:39 AM, Nathanaël Blanchet <blanchet at abes.fr>
> wrote:
>
>>
>>
>> Le 09/03/2017 à 10:25, Gianluca Cecchi a écrit :
>>
>> On Wed, Mar 8, 2017 at 6:05 PM, Gianluca Cecchi <
>> gianluca.cecchi at gmail.com> wrote:
>>
>>>
>>>
>>> NOTE: during the snapshot creation I see in web admin console the VM in
>>> paused state and also not responsive in both console and ssh session.
>>> After a couple of seconds it comes back and as a confirmation I see this
>>> in its messages:
>>>
>>> Mar  8 17:38:57 T-ORACLE73 chronyd[616]: System clock wrong by 19.077230
>>> seconds, adjustment started
>>>
>>> Is this expected?
>>>
>>>
>>>
>>>
>> Possibly the default changed at some point in time, so that now it saves
>> memory and so this implies pause of VM
>>
>> Saving memory is essential in some apàplications like DB, so you won't
>> bypass vm pauses for such a stuff
>>
>>
> Yes, indeed, the important thing is to have an option so that you can set
> it True or False, depending on the VM you are saving, the application that
> is running isnide it and the way you want to do backup of the application.
> Nevertheless, RDBMS and also other applications often have some mechanism
> to be "frozen in a consistent state" so that you can save what you have on
> disk without need to save memory to have a consistent backup.
> Oracle for example has functionality to be put in "backup mode" where you
> issue "begin backup" before the snapshot and "end backup" right after
> snapshot completion.
> I see that POstgreSQL has similar functionality (not tested myself):
> https://www.postgresql.org/docs/9.4/static/continuous-
> archiving.html#BACKUP-LOWLEVEL-BASE-BACKUP
> and the same for other ones.
>
> Gianluca
>
>
> _______________________________________________
> Users mailing list
> Users at ovirt.org
> http://lists.ovirt.org/mailman/listinfo/users
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ovirt.org/pipermail/users/attachments/20170309/845b1274/attachment-0001.html>