This post was originaly posted by me on blog.sogeti.com
The last few days Skype has had trouble getting their users connected to their online phones service. The reason being too many concurrent users. That enormous amount of users gave Skype problems; the Supernodes were offline because of a software bug. Now I can say that they should have tested for this defect, but how do you test for a defect that occurs with about 25 million concurrent (online) users, the typical load for Skype on a regular day?
A load test could have found that defect, but how do you organize such a load? Normal load testing software doesn’t have the option to go as high as 25 million (!); most will only get to 100,000 virtual users. And even if these tools reach these high volumes, virtual users will be very expensive. So how can these internet services, that have so many users, be load tested?
The cloud can provide an answer. Load testing tools that use the cloud can generate an enormous amount of virtual users to create that load, and cloud-enabled test tools are best to use with these great loads. The cloud will generate the load. With the use of the cloud infrastructure, a more ‘realistic’ load can be generated than the virtual load from complex tools. Some of these cloud-enabled performance test tools only work on the production environment (which may or may not be in a cloud environment), but other tools can perform these load tests on the Development, Test or Acceptance environments.
Use these cloud-enabled performance test tools to generate these enormous loads and find defects that only show up when your systems are most under stress. Thus at the worst moment!

