Fixing slow initial load for IIS

Writing a ping service/script to hit your idle website is rather a best way to go because you will have a complete control. Other options that you have mentioned would be available if you have leased a dedicated hosting box.

In a shared hosting space, warmup scripts are the best first level defense (self help is the best help). Here is an article which shares an idea on how to do it from your own web application.

Options A, B and D seem to be in the same category since they only influence the initial start time, they do warmup of the website like compilation and loading of libraries in memory.

Using C, setting the idle timeout, should be enough so that subsequent requests to the server are served fast (restarting the app pool takes quite some time - in the order of seconds).

As far as I know, the timeout exists to save memory that other websites running in parallel on that machine might need. The price being that one time slow load time.

Besides the fact that the app pool gets shutdown in case of user inactivity, the app pool will also recycle by default every 1740 minutes (29 hours).

From technet:

Internet Information Services (IIS) application pools can be periodically recycled to avoid unstable states that can lead to application crashes, hangs, or memory leaks.

As long as app pool recycling is left on, it should be enough. But if you really want top notch performance for most components, you should also use something like the Application Initialization Module you mentioned.

Web Hosting Challenge

You have to remember that none of the machine configuration options are available if you are hosted on a shared server as many of us (smaller companies and individuals) are.

ASP.NET MVC Overhead

My site takes at least 30 seconds when it hasn't been hit in over 20 minutes (and the web app has been stopped). It is terrible.

Another Way to Test Performance

There's another way to test if it is your ASP.NET MVC start up or something else. Drop a normal HTML page on your site where you can hit it directly.
If the problem is related to ASP.NET MVC start up then the HTML page will render almost immediately even when the web app hasn't been started.
That's how I first recognized that the problem was in the ASP.NET MVC startup. I loaded an HTML page at any time and it would load blazing fast. Then, after hitting that HTML page I'd hit one of my ASP.NET MVC URLs and I'd get the Chrome message "Waiting for raddev.us..."

Another Test With Helpful Script

After that I wrote a LINQPad (check out http://linqpad.net for more) script that would hit my web site every 8 minutes (less than the time for the app to unload -- which should be 20 minutes) and I let it run for hours.

While the script was running I hit my web site and every time my site came up blazingly fast. This gives me a good idea that most likely the slowness I was experiencing was because of ASP.NET MVC startup times.

Get LinqPad and you can run the following script -- just change the URL to your own and let it run and you can test this easily. Good luck.

NOTE: In LinqPad you'll need to press F4 and add a reference to System.Net to add the library which will retrieve your page.

ALSO : make sure you change the String URL variable to point at a URL that will load a route from your ASP.NET MVC site so the engine will run.

System.Timers.Timer webKeepAlive = new System.Timers.Timer();
Int64 counter = 0;
void Main()
{
    webKeepAlive.Interval = 5000;
    webKeepAlive.Elapsed += WebKeepAlive_Elapsed;
    webKeepAlive.Start();
}

private void WebKeepAlive_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
    webKeepAlive.Stop();
    try
    {
        // ONLY the first time it retrieves the content it will print the string
        String finalHtml = GetWebContent();
        if (counter < 1)
        {
            Console.WriteLine(finalHtml);
        }
        counter++;
    }
    finally
    {
        webKeepAlive.Interval = 480000; // every 8 minutes
        webKeepAlive.Start();
    }
}

public String GetWebContent()
{
    try
    {
    String URL = "http://YOURURL.COM";
    WebRequest request = WebRequest.Create(URL);
    WebResponse response = request.GetResponse();
    Stream data = response.GetResponseStream();
    string html = String.Empty;
    using (StreamReader sr = new StreamReader(data))
    {
        html = sr.ReadToEnd();
    }
    Console.WriteLine (String.Format("{0} : success",DateTime.Now));
    return html;
    }
    catch (Exception ex)
    {
        Console.WriteLine (String.Format("{0} -- GetWebContent() : {1}",DateTime.Now,ex.Message));
        return "fail";
    }
}