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Unicorn mailing list - [email protected] http://rubyforge.org/mailman/listinfo/mongrel-unicorn Do not quote signatures (like this one) or top post when replying
