On 01/09/2012 02:53 AM, Dan Callaghan wrote:
Excerpts from Steven Lawrance's message of Mon Jan 09 10:36:48 +1000 2012:
Bill's concern is the time spent polling RHEV to check whether it has the resources, on top of the existing SQL query for "real" systems, once for each queued recipe, on each iteration of the loop (currently every 20 seconds).
That SQL query is already fairly expensive, but it doesn't really hurt. Is the call to RHEV to say "can you provision this recipe?" actually slower than that SQL query? (Can RHEV handle the load from such frequent requests?)
Maybe we are worrying over nothing. Maybe adding lots of code in Beaker to track RHEV's available resources isn't really necessary?
I honestly don't think it is necessary. The being said, the 'call' is expensive, in the sense that RHEVM would try to launch the VM - and if it fails, would try on other servers as well. So a complete 'failure' would take time. I still think we are optimizing for a corner-case here and do suggest we'll have a POC - with intentionally limited RHEV setup, to see what happens. Obviously, I expect the real deployment to have a generous amount of hardware. Y.