Jonathan of Peritor Consulting just informed the world that there is in fact a bandwith limit in Amazon’s Elastic Compute Cloud (EC2) instances. In his case – using a small instance – a limit of 35 MB/s takes place. The folks of Peritor benchmarked it by hitting it with several EC2 instances and ‘normal’ servers located in other data centers. As we just had an interesting discourse on Twitter, Jonathan revealed that the bandwith must be related to the instane type you rent at Amazon’s. In XL instances there is a bandwith limit of about 70 MB/S, says Jonathan.
License
This work by Christian Stottmeister is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Germany.Powered by eleven2
One Comment
Testing ELBs by throwing a heavy load at it is not going to reveal the true behavior of the service. ELB is designed to scale up in response to load, gradually over the course of a few hours of increasing load.
The reason for this behavior is because “real world” web traffic behaves the same way – it doesn’t spike from 0 to 100 all within a minute, it gradually ramps up over the course of many minutes.
If you test ELB by hitting it full-on with high load, it will behave badly, dropping connections.
See my article on ELB’s design and how to test ELB deployments.
http://clouddevelopertips.blogspot.com/2009/07/elastic-in-elastic-load-balancing-elb.html