Hi everybody,
I need to write an ASP.NET application which must handle a very large number of transactions per second - as many as 5000 users may transact at the same time. I think I will use WCF in back to communicate with SQL server. But in front, can IIS handle 5000 users at the same time effectively, or is there any simple way to host my application outside of IIS?
It will depend on the characteristics of the machine but you could always setup a web farm to handle high loads.
You can host a WCF application outside of IIS using WAS, Windows Service or a .NET application.
It certainly would be possible to design a system using IIS that could handle the load you describe. Whether this is a good idea or not really depends on the application. I suggest perhaps you look at some benchmarking some of the loads to determine if it is quicker to host in IIS or if you host a WCF application outside of IIS.
Why you need it outside IIS. you can have 5000 TPS with IIS. But bear in mind that it depends from lot of aspects... like hardware, what configuration you have for your servers, it depends from heaviness of your application, what is the response time of your applications. Also as suggested you can have web farm. You can use load balancer and have several servers behind it. So it is possible just you need to have a proper design and if needed a budget for hardware upgrade.