BigIP fronting IIS 6.0 w ASP.NET

Not sure how helpful I can be since I am not an ASP expert, but in general, to LTM, ASP webserver just looks like any other webserver, so standard webserver load balancing optimizations would in order:

 

 

SNAT is not required, so if you want to limit by unique IP, you can set the webserver default route to the LTM floating self-IP and disable SNAT to preserve the true client IP.

 

 

OneConnect will pool connections on the backend, using keepalive connections for multiple requests. With the default mask, connections will be shared among all clients, substantially reducing the number of server-side connections.

 

 

Depending on your LTM version and traffic profile, you may want to tune the tcp profile for LAN traffic as detailed here: Click here

 

 

HTH

 

/deb

 

 

(If you find additional settings that are useful, please post back and I will start a new page specific to ASP server load balancing.)

 

Its possible to raise the number of connections higher than 2 and the following article from MS explains this a bit more. Its also worth noting that the number of connections is per AppDomain and not per physical webserver so depending on how your application is setup this may not be a problem.

 

 

http://support.microsoft.com/default.aspx/kb/821268

 

 

I would agree with Deb and try a OneConnect profile which may help.

 

 

Cheers

 

 

Simon

Thanks Simon and Deb for your thoughts. I have seen the MS article which we are using to help justify the default configuration change, but as that relates to a direct Client-Server route it doesn't take into account the Big-IP middle-man how I read it. The limit by the AppDomain does alleviate some of the issue as you note, but since some of our applications are implemented as virtual directories of the root virtual application I believe they share the same appdomain [could be wrong].

 

 

I will raise the configuration question to our team about the best practices for a web server profile. Preserving the client IP will be helpful in a couple places as it not only does not squeeze the connection pool in ASP.NET due to the SNAP single IP, but it also doesn't require a customized ISAPI filter to understand the X-Forward-For which our Web team has been wary to integrate.

 

 

Deb is there a whitepaper on general web server load balancing that I could point our config team toward? To the point of a related IIS/ASP.NET Best practices guide, if the hypothesis is true and someone using SNAT for their IIS servers could be significantly impacting performance as the maxconnection won't scale with clients as it is designed since IIS only "sees" one client/virtual application. We are still working on proof of this hypothesis, but if I do prove it out I will post back and maybe an addendum to the generic web server configuration best practices.

I found these docs specific to IIS:

 

 

IIS Optimization Solution Brief

 

http://www.f5.com/solutions/sb/pdfs/iis_sb.pdf (Click here)

 

 

IIS Deployment Guide http://www.f5.com/solutions/deployment/iis_bigip9_dg.html (Click here)

 

 

The solution brief is high level, and specifically calls out compression, caching, and TCPExpress (the optimized tcp profile I mentioned earlier).

 

 

The deployment guide contains the configuration details.

 

 

HTH

 

/deb

Appreciate all of the follow-up Deb.

 

 

I will give this a read and hopefully this will help make the case of a IIS config change to our web management org.

 

 

Thanks again,

 

 

Justin