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[udit agarwal <fzdudit@xxxxxxxxx>]

Hi Sebastien,

  Thanks again for your reply. Sorry for disturbing you again but I am in a
bit of hurry now. As you talk about that swift supports object storage so I
can store the VMs data using swift. So if I have my VM instance running on
my nova client and if I want to copy some massive data from my client side
to VM can I use swift to store the data on behalf of VM subsequently. If
so, can you help me out with this??

  Again thanking you for your immense help.

--Udit

On Fri, Jun 29, 2012 at 11:35 AM, Sébastien Han <han.sebastien@xxxxxxxxx>wrote:

> Hi!
>
> The local file system of each instance is ephemeral, when you run the
> action *terminate* you will loose everything. But you can shutdown,
> reboot the instance without any problem. If you want to use Cinder
> (previously known as nova-volume), you need a storage solution which
> supports *block device*. Here a little reminder:
>
>
>    - Ceph features:
>       - object storage
>       - block device
>       - distributed filesystem
>    - Swift:
>       - *only* an object storage. So you can use it to store the VMs data.
>
> If you want to use cinder you can use this king of storage:
>
>    - SAN with LVM + iSCSI
>    - Ceph
>    - Sheepdog
>    - ...
>
> Check my article about that to see the big picture of the available
> storage solution:
> http://www.sebastien-han.fr/blog/2012/05/17/openstack-high-avavailability-1/
> With one of those technology you will be able to attach persistant storage
> to your instances.
>
> Cheers!
>
>
> On Fri, Jun 29, 2012 at 1:26 AM, udit agarwal <fzdudit@xxxxxxxxx> wrote:
>
>> Hi Sebastien,
>>   Thanks for your reply. Your replies have always proved beneficial to
>> me. I want to know one more thing. In a virtual machine, storage is not
>> persistent, so we need to attach a volume with it for storage purposes. My
>> question is that is it possible to create our volumes in ceph or in swift
>> (so that we can have enough space for virtual machine storage).
>>   Thanks in advance.
>>
>> --Udit
>>
>>
>> On Thu, Jun 28, 2012 at 9:48 PM, Sébastien Han <han.sebastien@xxxxxxxxx>wrote:
>>
>>> Hi,
>>>
>>> I'm sure if I understand everything but let me give a try.
>>> By default, the compute nodes store virtual instances in
>>> /var/lib/nova/instances/. Of course it's part of the compute node local FS.
>>> If you want to store this directory somewhere else, use a DFS like
>>> GlusterFS or even Ceph or a SAN.
>>> Also don't forget that you *can't *use Swift for storing your virtual
>>> instances.
>>>
>>> Hope it is what you asked for.
>>>
>>> Cheers.
>>>
>>> On Thu, Jun 28, 2012 at 1:48 AM, udit agarwal <fzdudit@xxxxxxxxx> wrote:
>>>
>>>> Hi,
>>>>  I have set up Openstack in my lab with everything except storage nodes
>>>> on one system and two other systems with each of them acting themselves as
>>>> a storage node. I have used swift as the backend for glance so all the
>>>> uploaded images are stored on these storage nodes. But when I run a virtual
>>>> machine using nova, it reads the image from the storage nodes and it seems
>>>> to me that it uses the local filesystem for storing instances and after I
>>>> shutoff my virtual machine, it writes back to the storage nodes. But the
>>>> thing that I want to implement is that if I copy some file from my local
>>>> system to that virtual machine, it should automatically get stored on my
>>>> storage nodes rather than occupying space on my local filesystem.
>>>>
>>>>  Can anybody help me with this??
>>>>  Thanks in advance.
>>>>
>>>> --Udit Agarwal
>>>>
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>>>>
>>>
>>
>