The cloud promises a new era of cost reduction and agility for IT, and enterprises are diving in (warning: PDF) to secure these benefits. But the process for moving applications to the cloud can be messy, particularly for those companies that haven't battle-tested their applications to ensure they can run in the cloud at scale …
I thought the major selling point of cloud platforms for scalable apps was that you can adapt your infrastructure under load through provisioning as opposed to adapting your platform to the hardware you've got. All the testing in the world won't expose particular imbalances that occur as a result of marketing activity, for example - so I don't see a compelling use case for cloud testing, from my perspective at least. Monitoring, yes, because it's difficult to even see problems that occur in a segment of your infrastructure on which other segments do not absolutely depend.
My question is would you rather duplicate your production environment on the cloud for load testing, or just overprovision for more spare capacity than you think you'll need, then deal with the fallout with more if required?
Believe shite like this you'd think no-one in the universe ever had to design a scalable app until this 'cloud' thingie came along. Newsflash Sherlock, businesses have been doing this sort of thing for ages. The only difference with a cloud is where the app lives. So when porting an already scalable app to a cloud provider you aren't going to waste time re-running your load tests, you're going to make it the provider's responsibility via a suitable SLA.
It's also perfectly possible to use, at least some of these products, to load test an application that isn't hosted in the cloud, for example your average web site. Using a cloud-based load tester can be much cheaper than the traditional options. Site Confidence is one I'm aware of.