Can ASP.NET applications continue running even if IIS is reset in ASP.NET 4.0?

Yes, his is possible in applications built on top of ASP.NET 4.0 (and onwards). Historically, ASP.NET applications take time to load at the first time a request is passed to the web server.

Pre-Requisites: IIS 7.5+, Windows Server 2008 R2

Advantage

Web application keeps running when IISRESET is run. For this, you need to set the IIS Application Pool as AlwaysRunning. When the new IIS Worker Process is up, the new changes start reflecting. This effectively means that there would be NO INTERRUPTION.

In the file applicationHost.config

<applicationpools>
<add name="MyApplicationPool" startMode="AlwaysRunning" />
</applicationpools>

Next, you can specify which applications need to be pre-started, when IIS is setup:

<sites>
<site name="MySite" id="1">
<application path="/" serviceAutoStartEnabled="true" serviceAutoStartProvider="PrewarmMyCache" />
</site>
</sites>
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