openstack team mailing list archive

[Leandro Reox <leandro.reox@xxxxxxxxx>]

Yep thats right pablo !


On Thu, Jul 4, 2013 at 2:02 PM, pablo fernandez
<fernandezpablo85@xxxxxxxxx>wrote:

> Guys,
>
> I also found that the blocking_device_mapping table only contains entries
> for the volumes that are "in-use".
>
> Since we're planning a less transparent cloud migration, with detached
> volumes seems I don't have to copy this information. The only change needed
> is to copy the volumes_* info and perform the id translation in between
> (from ints to UUIDs). Am I right?
>
> Thank you!
>
>
> On Thu, Jul 4, 2013 at 1:16 PM, pablo fernandez <
> fernandezpablo85@xxxxxxxxx> wrote:
>
>> Leandro, Brano,
>>
>> I'm effectively migrating only the openstack installation, the DFM
>> remains the same. However, if I read Brano's email correctly, besides
>> migrating the information on openstack DB I also have to change metadata
>> that DFM, is that right?
>>
>> Here's an example of a volume I have on Essex right now:
>>
>> https://gist.github.com/fernandezpablo85/fd4340f0150bdf574bbb
>>
>> And here's what DFM returns for that volume's LUN:
>>
>> https://gist.github.com/fernandezpablo85/219f78545166f0c030b3
>>
>> Is moving the data just from Essex db to Folsom safe in this case?
>>
>>
>>
>> On Thu, Jul 4, 2013 at 12:08 PM, Leandro Reox <leandro.reox@xxxxxxxxx>wrote:
>>
>>> Pablo,
>>>
>>> On folsom the block_device_mappings table its on novadb too, i totally
>>> miss the Brano's recommendation of uuid conversion and metadata, asumming
>>> that you hit the same dfm.
>>> We had to do that a couple of times, but generally as all our vms are
>>> stateless, we create them on the "new" cloud, and replicate the content,
>>> via sharding replicas or other mechanism, without intervention
>>>
>>> Saludos
>>>
>>>
>>> On Thu, Jul 4, 2013 at 11:27 AM, Brano Zarnovican <zarnovican@xxxxxxxxx>wrote:
>>>
>>>> On Wed, Jul 3, 2013 at 11:24 PM, pablo fernandez
>>>> <fernandezpablo85@xxxxxxxxx> wrote:
>>>> > Hi list!
>>>> >
>>>> > Any advice on this? Has somebody already tried it (and hopefully
>>>> succeeded).
>>>>
>>>> We did this migration "in-place". On day D, we dumped Essex
>>>> Openstack/DFM DB and restored in Folsom. I have created a patch for
>>>> Folsom Netapp driver to recognize Essex volumes/snapshots.
>>>>
>>>> I assume that both your clouds are hitting the same DFM. Otherwise,
>>>> you would have to migrate entries not only between Openstack DB, but
>>>> DFM DB, too. Would be painful..
>>>>
>>>> Folsom Netapp driver has added some meta-data to Openstack datasets
>>>> (in DFM), so Folsom will not recognize DFM datasets created in Essex
>>>> (and hence all Essex LUNs would be invisible). I have added that
>>>> meta-data manually with the attached script.
>>>>
>>>> Volume is identified by (host, provider_location). Host is the one
>>>> running nova-volume, provider_location is an object id in DFM db.. eg
>>>> ("mgmt-netapp.example.com", 7574).
>>>>
>>>> So if you are using the same DFM, provider_location won't change, but
>>>> you host probably would.
>>>>
>>>> Problem would be that you need to migrate id from decimal to UUIDs. In
>>>> my case, this was done in Openstack DB as part of that in-place
>>>> migration. The mapping is stored in new table "volume_id_mappings".
>>>> Same comments apply also to snapshots. However, because of this UUID
>>>> change, volumes names (LUNs on Netapp) are expected in different
>>>> format.
>>>>
>>>> Essex:
>>>> /OpenStack_103a49bb861e485ea05aa78f9b0216bd/vol-000009a4/vol-000009a4
>>>> Folsom:
>>>>
>>>> /OpenStack_103a49bb861e485ea05aa78f9b0216bd/vol-dcc14978-4ff1-422b-97e7-f7f668718b9e/vol-dcc14978-4ff1-422b-97e7-f7f668718b9e
>>>>
>>>> That was the reason for driver patch, so I did not have to rename
>>>> existing LUNs on Netapp and DFM.
>>>>
>>>> It's almost easier to create all volumes in Folsom and dd the content
>>>> ;-)
>>>>
>>>> Regards,
>>>>
>>>> BranoZ
>>>>
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>>>>
>>>
>>
>