Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

We have 25 instances with one load balance on Ec2. If we hit any single one the speed is fast(<300ms) but if we us AB to test multiple connections we get poor results often with an average of 1800ms. Does anyone know if this is EC2 limiting us, we're only hitting these servers from 27 outside servers with about 2 million requests and hour so maybe they think it's a DOS?

share|improve this question
Hi Ryan. Are you using an Elastic Load Balancer, or a software-based load balancer? – Matt Solnit Nov 10 '09 at 16:52
If it is software based, Network throughput may be the issue. I don;t know the performance statistics on the ELBs, although it seems like they may be open to the same issues. – Flashman Apr 13 '11 at 16:38

We've loaded tested applications with up to 2.8 million requests with an average round trip latency of under 100ms. Based on this, and the fact that you're using slightly fewer requests, I doubt you're being throttled.

Having said that, this question was asked in 2009 (over 2 years ago at the time of writing), so it's entirely possible that AWS was doing things differently back then.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.