High CPU and memory usage in Kentico CMS.

Our problem started few weeks ago, there was no change on server side, so it just came from "nowhere".

We have Windows Web Server 2008 R2 with IIS 7 (7.5.7600.16385), this server is hosting 19 websites, 2 of them are Kentico CMS, both used to use very much CPU and memory use is growing all the time. Temporary solution was to configure memory limit in IIS, so when it goes over 4GB, w3wp process is restarted.
I need to know what is cause for that.
First thing I found out: both w3wp processes have many threads clr.dll!DestroyAssemblyConfigCookie+0x130ec, sometimes cycles delta for all those threads takes up to 2,000,000,000. It's about 2Ghz CPU.
Clr.dll is .NET library, but I couldn't find any documentation about modules inside. It's version .NET 4.0.30319.

Another thing is how can I check which library/thread is using most memory, where leakage can occure? Both websites are in production and visited all the time, so I'm not allowed to experiment or do any changes in code.
Tomasz CzyzSystem AdministratorAsked:
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Dan McFaddenSystems EngineerCommented:
So, first things first... the CLR.DLL is the .NET engine (for lack of a better description), so it is not a surprise that a .NET based CMS has multiple threads running thru the CLR.  Not an issue.

Before you start ripping apart a 3rd party application, I would ask a few questions first:

1. what version of the CMS are you running?  Current version is 8.2 (January 6, 2015).
2. have you analyzed the CMS sites http logs to see what is going on?
3. can you correlate memory pressure with site activity?
4. can you correlate CPU pressure with site activity?
5. where is the database(s) that supports the CMS's?  local instances or remote?
5a. if the SQL Server instance is local, what is its memory and CPU utilization footprint?

Also, since Kentico CMS is a commercial software package, have you opened a support ticket with the vendor?

Has your company built custom functionality into the CMS?


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Tomasz CzyzSystem AdministratorAuthor Commented:
Thank for help.
We had version 5 installed and we have custom functionality with special authentication and session/cookie handling which is causing problems.
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