[openstack-dev] [Nova] Does Nova really need an SQL database?

Soren Hansen soren at linux2go.dk
Wed Nov 20 16:06:28 UTC 2013

2013/11/18 Mike Spreitzer <mspreitz at us.ibm.com>:
> There were some concerns expressed at the summit about scheduler
> scalability in Nova, and a little recollection of Boris' proposal to
> keep the needed state in memory.

> I also heard one guy say that he thinks Nova does not really need a
> general SQL database, that a NOSQL database with a bit of
> denormalization and/or client-maintained secondary indices could
> suffice.

I may have said something along those lines. Just to clarify -- since
you started this post by talking about scheduler scalability -- the main
motivation for using a non-SQL backend isn't scheduler scalability, it's
availability and resilience. I just don't accept the failure modes that
MySQL (and derivatives such as Galera) impose.

> Has that sort of thing been considered before?

It's been talked about on and off since... well, probably since we
started this project.

> What is the community's level of interest in exploring that?

The session on adding a backend using a non-SQL datastore was pretty
well attended.

Soren Hansen             | http://linux2go.dk/
Ubuntu Developer         | http://www.ubuntu.com/
OpenStack Developer      | http://www.openstack.org/

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