ASP.NET application performance issue on Windows Azure

Question

We have an application deployed on Windows Azure as a Web Role and we are using Pingdom for testing page load times: http://tools.pingdom.com/fpt/

The url for the application on Windows Azure is: http://www.doctorspring.com . The load time of the app is usually around 7s. The database is an SQL Azure database and the role and the database are in the same zone.

Sample pingdom result: http://tools.pingdom.com/fpt/#!/CllGggrMz/http://www.doctorspring.com/

Sample pingdom result(with gzip):http://tools.pingdom.com/fpt/#!/f2TUbR6OX/www.doctorspring.com

Suspecting that Azure could be the problem, we tried a free hosting from Somee as: http://www.doctorspring.somee.com The load time of the app on Somee is around 3.5s.

Sample pingdom result: http://tools.pingdom.com/fpt/#!/o3gZOjTwH/http://www.doctorspring.somee.com/

That is a huge performance issue for us. Can you please help us understand the problem with Azure or suggest a method, as to how can we overcome it?

Thanks, Manish

Answer 1

In both cases, loading the homepage is unacceptably slow - 3.5 seconds to generate a page is around 10 times slower than you need to be when there's no load on the site. I'd expect the site to crumble under even moderate load with this kind of performance.

Without knowing how the site is constructed, it's hard to explain the reason one environment is faster than the other - but my guess is that whatever is generating the page (some kind of CMS?) is the cause. Azure is known to be a touch slow when doing database queries - though normally this only manifests itself under extreme conditions.

I'd recommend tuning the CMS - especially with caching. We found that Azure is normally pretty fast, but when doing database lookups (e.g. retrieving content for the CMS), it can be variable; if your CMS is doing a LOT of database queries to get the homepage content, it's going to be slow.

It's also worth running Yslow - there's some low-hanging fruit on getting performance up.