WCF - Optimize Config and IIS

Question

I have a WCF RESTful service that is hosted in IIS that is hit by several of our applications. The WCF services appear to operate fine for the most part, but sometimes it takes a long time to get a response from the service.

I was seeing if there was a good tutorials or resources to follow on how to best configure WCF RESTful services to be web scale either through the web.config, from IIS, or from our dedicated application pool.

We have gone through our services and used NHibernate profiler to find and optimize any problematic queries and we also have memcached setup to also help with performance. The problem seems to be when many applications are consuming the service in a short period of time or when the service has sat idle for a long period of time.

Thanks for any assistance.

Answer 1

Not sure if its applicable to your scenario, but I read the below mentioned blog post on MSDN a couple of days ago. It's about a problem in the Net IOCP Threadpool which causes long response times for WCF when many requests are issued in short time. Maybe that could help you?

WCF scales up slowly with bursts of work

KB2538826

Answer 2

There is no general advice on heavy load issue, but one of the possible optimizations would be using asynchronous operations on the server side: Scale WCF Application Better with Asynchronous Programming. It's about conserving thread pool resources while making database calls.

As for the idle period issue, check out Configuring Recycling Settings for an Application Pool (IIS 7)