[openstack-dev] Moving task flow to conductor - concern about scale

Dan Smith dms at danplanet.com
Fri Jul 19 15:06:50 UTC 2013

> Nova-conductor is the gateway to the database for nova-compute
> processes.  So permitting a single nova-conductor process would
> effectively serialize all database queries during instance creation,
> deletion, periodic instance refreshes, etc.

FWIW, I don't think anyone is suggesting a single conductor, and
especially not a single database proxy.

> Since these queries are made frequently (i.e., easily 100 times
> during instance creation) and while other global locks are held
> (e.g., in the case of nova-compute's ResourceTracker), most of what
> nova-compute does becomes serialized.

I think your numbers are a bit off. When I measured it just before
grizzly, an instance create was something like 20-30 database calls.
Unless that's changed (a lot) lately ... :)


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