Hi, Thanks Russel, Paul, and everyone else who helped with the Asterisk testing on Friday. Here's how I see the outcome:
The main problem we're trying to solve is that the audio is sometimes choppy. We found that moving the PBX to some specific Rackspace vms improved the situation. Moving to an 8g vm in the same dc did not improve the situation; moving to a 30g vm in the same dc did improve it. Moving to a small vm in a new dc which is lightly loaded also did improve it. And finally, moving to a small vm in HPCloud also improved it. This leads me to believe that the load on the host hardware affects this problem, possibly due to additional latency in providing cpu time slices. The fact that both using a larger VM (which reserves more of the host's resources) and a less heavily loaded data center (less competition for host resources) improved things points in this direction. After this test, Paul disabled the silence suppression, and when we moved back to our original vm, the problem did not manifest. Combining this result with the above suggests to me that perhaps the silence suppression algorithm is particularly sensitive to cpu latency. Regardless, here are some possible next steps: * Move Asterisk to a 30g vm in Rackspace (in either our current or the new data center). This appears to reserve a large enough CPU capacity to help with the problem, though it's possible future host load changes may still affect us. * Move Asterisk to a vm in HPCloud. This has the additional downsides that we can provide no IPV6 service, the Asterisk (and network) configuration becomes more complicated due to NAT, and HPCloud still occasionally terminates vms without warning. It is also possible here that future host load changes may affect us (but that is more speculative since we haven't seen evidence of that so far). * Disable silence suppression in the conference server. This appears to have a much smaller effect on load than we anticipated (we tested with 60 participants and did not observe a problem). However, silence suppression is useful on large calls to reduce background noise from non-speakers. Does anyone have any other observations or suggestions? -Jim _______________________________________________ OpenStack-Infra mailing list [email protected] http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-infra
