Hi,

I'm hoping someone may be able to help us out.. Basically we run DNN 6.2 PE in a web farm (2 x web heads, win 2008 R2, quad CPU, 8Gb Ram - These are Cloud Server), Win 2008 R2 File Server, 2 x Quad CPU, 8Gb Ram - Dedicated Box, and seperate dedicated SQL Box. We have setup DNN to use UNC which is located on File Server.

What we are experiencing, well to be blunt, dreadful performance and very excessive CPU usage with really minimal requests, the CPU's ramped up as the day goes on and appear to have a pattern to them, eg high usage 5-6 seconds then back down for 2-3 secs then back up again.

We are monitoring requests coming in and at high CPU times, for the amount of requests, the CPU shouldn't be behaving this way. Memory usage is however all good, and app pools are around 400-500K.

So our first point of call is the high CPU, we have verified the CPU usage is from the DNN worker process (app pool) so we decided to look inside it to see what is happening using Process Monitor from SysInternals.

What we found was in almost all cases there is repeated calls to clr.dll!StrongNameSignatureVerification and not just once, but happening several times each with their own CPU hit.

We are at a stage of getting desperate for answers, we have followed all DNN Best Practises, looked at optimizing IIS but it seems whatever is making the constant calls to clr.dll!StrongNameSignatureVerification is our killer.

Can anyone help or try shed some light on this.

Many Thanks.

Hi

 had a very similar problem, I conducted a full memory dump analysis  on the IIS worker process.

Got an expert to pin point the troublesome module or method, called the vendor module, had them fix the infinite loop causing the high CPU.

It was from an unexpected source

Another thing I have seen cause this is the Host > Schedule scheduled items running on all or multiple servers.  Make sure that you limit them all to run on a specific server.