We experience the same problem. I believe the problem has more to do with the kernel CPU scheduler than anything else. If you figure put a reliable way to spread the load, I'd like to hear it.
Clifton King Development [email protected] 512-940-7744 Sent from my phone. On May 31, 2011, at 7:20 AM, Nate Clark <[email protected]> wrote: > Lawrence, > > I've suspected that it may be a monitoring problem and not a Unicorn > problem, but I'm not yet convinced either way. Our monitoring via > collectd is done through Rightscale. They have a lot of experience > with EC2, so I'd assume that it is monitoring properly. Also, our > other services (mysql, for example) are showing activity on multiple > cores under load, so that leads me to believe that the monitoring is > working in at least some cases. > > I wasn't aware of the Cloudwatch service until now, that looks > interesting ... I'll check it out. > > Anyone else experience a problem like this? > > Nate > > On Tue, May 31, 2011 at 8:10 PM, Lawrence Pit <[email protected]> wrote: >> Hi Nate, >>> >>> We've been watching the CPU >>> graphs from collectd data when the website is under load, and only >>> cpu-0 shows any activity ... the others seem to be idle, or minimally >>> used by other services. >> >> I don't think you can rely on the numbers collectd (nor top) gives you when >> measuring from within the hypervisor powering your EC2 instance. The only >> reliable source of CPU utilization is Cloudwatch, as that measures outside >> your instances. >> >> I've used an array of xlarge instances myself, each running 17 unicorn >> workers serving a rails app, consuming 4GB, leaving 3GB, no swap. Worked >> well for us under high load. It couldn't have handled that if all 17 unicorn >> workers would've been served by 1 of those 8 virtual cores. >> >> >> Cheers, >> Lawrence >> >> > _______________________________________________ > Unicorn mailing list - [email protected] > http://rubyforge.org/mailman/listinfo/mongrel-unicorn > Do not quote signatures (like this one) or top post when replying _______________________________________________ Unicorn mailing list - [email protected] http://rubyforge.org/mailman/listinfo/mongrel-unicorn Do not quote signatures (like this one) or top post when replying
