On Tue, Jul 12, 2011 at 7:51 PM, Ken Perkins <k...@clipboard.com> wrote: > What could be causing the delay on the rackspace VM? Is it purely a VM > performance issue, or is there something else going on.
The blessing of the cloud: It hides the Hard Stuff. The curse of the cloud: It hides the Hard Stuff. :) First order of business -- how easy is it to reproduce? If you dump the fs cache and spin up pre-populated nodes, do you get predictable (if poor) latency? If you run a series of random queries, or even a series of repeating queries, does it have the variance you expect? Does it get better/worse? Based on the limited info you stated, same data set, same configuration, etc -- the only variable present seems to be the virtualized system. 30-40 second delay is pretty crazy, though. Have you confirmed that both deployments have similar CPU and I/O profiles? My hunch is that you will see significant I/O wait on the slow one. You might also consider doing a strace (or equivalent) on the slow nodes and see what (if anything) is happening while that search is going on. I realize this is really just a bunch of questions, not an answer. :) Diagnosing performance problems in a virtualized environment is tricky, at best. Add to this the possibility that you may have a bunch of nodes running on a single piece of hardware (competing for resources and reliability) and things get really, really, hard to predict. Hope that helps... D. -- Dave Smith Director, Engineering Basho Technologies, Inc. diz...@basho.com _______________________________________________ riak-users mailing list riak-users@lists.basho.com http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
