windows azure website load time

Question

Sometimes when I access my windows azure website, the initial response time is very slow. After the first page load the website is fast. Some background: The website is not

Answer 1

The Windows Azure Web Sites are still in preview, so there is currently no SLA with that service.

The Web Sites do idle out when in free or in Shared mode, which is likely what you are seeing. When the site idles out it actually is removed from memory, and indeed the IIS process host running the site is shut down. This is how they can get the density of hosting 100 sites on the same VM.

You can find a lot of info on the Channel9 site about why this is the case, or, as a shameless plug, here is an article that talks about how the process is handled.

Now, you mentioned that you were using a keepalivecontroller, but what exactly do you mean by that? I use pingdom.com to contantly request data for one of my websites, and that seems to do pretty well. It is still possible that a request doesn't come in and the idle time is met which then cycles the site. It is also possible that even if you always have the site running that the VM the site sites on needs to have the underlying OS updated, in which case Azure would then move the site process to another VM, which could also cause the slow start up on the next request.

I'd start logging your application start ups and then look through your logs to see how often that is happening.