[openstack-dev] [nova][object] One question to the resource tracker session

Jiang, Yunhong yunhong.jiang at intel.com
Fri Nov 15 00:19:16 UTC 2013



> -----Original Message-----
> From: Dan Smith [mailto:dms at danplanet.com]
> Sent: Thursday, November 14, 2013 10:43 AM
> To: OpenStack Development Mailing List (not for usage questions)
> Subject: Re: [openstack-dev] [nova][object] One question to the resource
> tracker session
> 
> >> You're right, it's not really achievable without moving to a schemaless
> >> persistence model.  I'm fairly certain it was added to be humorous and
> >> should not be considered an outcome of that session.
> >
> > But we can avoid most data migrations by adding any required
> > conversion code into the objects DB layer, once we start using it. But
> > it might not be what we want.
> 
> Right, I'm sure it was added to the notes in response to discussion in
> the room about hating migrations in general. We can't avoid them
> entirely, but we do need to start moving away from making them
> monolithic and scary. This is important not only for performance when
> running migrations on large databases, but also for live upgrade. The
> general agreement from the summit sessions was that we need to make
> conductor able to tolerate all the schema versions from N-1 to N (where
> N is a release) so that it can be upgraded first, the schema next, and
> then (when possible) data migrations happen live instead of in bulk.

Thanks for clarification and seems very promising.
I assume this back support include also object and the N means major release like H, I, right?

--jyh





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