title: How to: Avoiding Cold-Start issues with IIS hosted WCF applications?
body: <p>We have a system where we host a couple of WCF applications in IIS. Some of these applications have a bit of an extended start-up time taking a couple of seconds (more than a users would be happy to wait for). Once it's up and running, everything is snappy though, so it really is only the startup time.</p>
  
  <p>The client also has a requirement to recycle the application pools every night.</p>
  
  <p>Is there some way to wake all these services up so that the start-up time is not an issue for the first user of the system?</p>
  
  <p>Initial thoughts where to write a windows service that would simply call a lightweight method on each service every x (configurable) minutes to keep the apps alive, but since we are in a load balanced environment, and the applications need specific host headers to be passed, we would always hit the load balance address which means there is no way for us to make sure that all services on all boxes in the cluster are actually started.</p>
  
  <p>Since a single wcf application in IIS can only have a single host header, the only other way would be to setup a second iis web site pointing at the same application. I'm just not sure if that would do the trick since it would be in another host context.</p>
  
  <p>another option could be to wright something like an extension to IIS (not sure if this is possible yet) that could call each of our services when IIS or the app pool actually starts up again. (Something that notices when the app pool has recycled but before the first user request.</p>
  
  <p>Any ideas would be much appreciated.</p>
  
  <p>Thanks</p>
  
  <p>Gineer</p>