Code review comment for lp://qastaging/~justin-fathomdb/nova/constraint-scheduler

Justin, nice work on a very interesting branch.

We're currently working on a similar approach in our Zones and Distributed Scheduler blueprints.

https://blueprints.launchpad.net/nova/+spec/multi-cluster-in-a-region
https://blueprints.launchpad.net/nova/+spec/bexar-distributed-scheduler

Ed Leafe (dabo) is working on a similar body of work to this, based on the current Rackspace/Slicehost implementation of Server Best Match.

Soren has a point that the search doesn't have to be exhaustive. We recently changed our approach from server-side to nearly fully db-side and saw massive performance improvements. Also, limiting the result set to XX% as Soren mentioned was possible once the problem was pushed off.

I think we need to review your branch in some depth before giving a pass/fail. I've sure there are things we can leverage to bring it in line with Distributed Scheduler.

Cheers! ... and stay tuned.