[one-users] Backing up virtual machines.

[Ruben S. Montero]

Hi Tao

The OpenNebula VM backup can be performed in  two different ways:

1.- via disk snapshots. Note that these are copies of the VM disks, and
they are stored in an Image Datastore.
  * The volume needs to be offline to guarantee FS consistency (e.g.
poweroff the VM or umount it from the VM). No need to shutdown the VM,
though: onevm disk-snapshot --live (onevm saveas is deprecated, use onevm
disk-snapshot instead).
  * If needed the operation can be automated by a simple script or an
scheduled action.
  * The VM can be recovered manually from OpenNebula (defining a new VM
based on the saved disk). Note that the life-cycle of the saved disk is
different from the original VM (no need to have it running for example)

2.- via the underlying storage system. You can create a special system DS
with its own backup policies (e.g. leveraging NAS features or FS features).
Note:
  * You would probably require some kind of synchronization from the VM to
prevent FS corruption.
  * The backup procedure is handled transparently to OpenNebula
  * The recovery process cannot be initiated from OpenNebula and need to be
in place.

In your case you could increase the reliability (different from backup)  by
configuring some of the local volumes used for the SSH Datastore with DRDB
or a RAID configuration.

Cheers

Ruben


On Mon Nov 10 2014 at 10:41:46 PM Tao Craig <tao at ispot.tv> wrote:

> Hi,
>
>
>
> I have a question about backing up and restoring virtual machines.
>
>
>
> I am using OpenNebula 4.8 and the SSH transfer drivers as a means to
> deploy virtual machines. My images are not persistent and I am using the
> qcow2 image format. All of my virtual machines and physical hosts are
> running CentOS 6.5 and using ext3 file systems.
>
>
>
> Is it possible in my current environment to back up a virtual machine
> without shutting it down?
>
>
>
> I know I can snapshot a virtual machine, but what if that machine is
> suddenly deleted for some reason (i.e. physical host crashes and has to be
> rebuilt). I’m under the impression snapshots are only usable as long as the
> original virtual machine is still running.
>
>
>
> I know I can also use the onevm saveas command, but that only works if you
> plan on shutting the virtual machine down at some point.
>
>
>
> Ideally, I would like to do something like copy the (running) disk image
> to offline storage and then have the ability to swap that out with a new
> running virtual machine to restore the back up in case the original virtual
> machine is lost. Rebooting in the case of restoring is acceptable of
> course, but I can’t shut my machines down every time I want to back them up.
>
>
>
> Is something like this possible?
>
>
>
> Thanks.
>
>
>
>
>
>
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> Users at lists.opennebula.org
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>
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