[openstack-dev] [nova] Distributed Database

Thierry Carrez thierry at openstack.org
Sat Apr 23 15:10:37 UTC 2016

Monty Taylor wrote:
> On 04/22/2016 03:27 PM, Ed Leafe wrote:
>> OK, so I know that Friday afternoons are usually the worst times to
>> write a blog post and start an email discussion, and that the Friday
>> immediately before a Summit is the absolute worst, but I did it anyway.
>> http://blog.leafe.com/index.php/2016/04/22/distributed_data_nova/
> Whee!! Well look - at least someone is still on email. Lucky you.
>> Summary: we are creating way too much complexity by trying to make Nova
>> handle things that are best handled by a distributed database. The
>> recent split of the Nova DB into an API database and separate cell
>> databases is the glaring example of going down the wrong road.
>> Anyway, read it on your flight (or, in my case, drive) to Austin, and
>> feel free to pull me aside to explain just how wrong I am. ;-)
> So - I don't think you're wrong, but I don't think you're right either.
> I think replacing nova's persistent storage layer with a distributed
> database would have a great effect - but I do not think it would have
> anything to do with the database itself. It would come from the act that
> would be completely necessary to accomplish that- completely rewriting
> the persistence layer.

So... The folks from the Discovery initiative working on a 
massively-distributed cloud use case have been working on incremental 
changes to make that use case better supported by stock OpenStack. That 
includes an oslo.db driver backed by a distributed database. Being 
scientists, they ran interesting experiments to see when and where it 
made sense.

They will present their findings in the upstream dev track, and I think 
it makes a good data point for this discussion:


Thierry Carrez (ttx)

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