Open Stack

On 25 October 2013 10:04, Chris Behrens <cbehrens at codestud.com> wrote:
>
> On Oct 24, 2013, at 1:33 PM, Robert Collins <robertc at robertcollins.net> wrote:
>
>> -2 to 10 minute downtimes.
>>
>> +1 to doing the evolution gracefully. There is a spec for doing that
>> from the H summit; someone just needs to implement it.
>
> +1.  IMO, we need to move to a model where code can understand multiple schemas and migrate to newer schema on the fly.  The object code in nova will be able to help us do this.  Combine this with some sort of background task if you need to speed up the conversion.  Any migrations that need to run through all of the data in a table during downtime is just not going to scale.
>
> I am personally tired of having to deal with DB migrations having to run for 1 hour during upgrades that happened numerous times throughout the Havana development cycle.

We had a clear design at the H summit, and folk committed to working
on it (Johannes and Mark W); not sure what happened...

https://etherpad.openstack.org/p/HavanaNoDowntimeDBMigrations

-Rob
-- 
Robert Collins <rbtcollins at hp.com>
Distinguished Technologist
HP Converged Cloud