Hi I wonder if you can help me out.

We have a coporate intranet and we have just upgraded from 3.3.7 to 4.9.2. Everything went well with the upgrade and the testing of the upgrade until this morning when people were authenticated for the first time. About 200 people went through the login process at between 9:15 - 9:30 GMT and all hell broke loose. The WindowsSignin.aspx page was timing virtually everyone out except those that had already been authenticated. Our IIS server was running at 100% (Dual Xeon 3GHz Processors with 4Gb ram on Windows 2003) and the memory usage ramped up to 500Mb on the IIS Application Pool (w3wp.exe). I am using version 1.05 of the Active Directory authentication module.

When individual users are authenticated, the IIS App Pool memory goes up by 2-3Mb and the processor hit between 50-75% during authentication. When many people are attempting authentication the processor hits 100% constantly, the IIS App-pool goes through the roof and people get timeouts. The issue seems to be that the ISS App pool does not free up the memory after authentication and I phically have to kill the ISS memory process.

Has anyone seen anything like this before and do you have any suggestions?

Thanks

I've run into sluggishness here also, due to the high number of authentications (at peak periods, we run up to about 100 logins a minute).  I've narrowed our main culprit down to being mostly a problem with our domain controller being over-taxed, and the SQL Express not able to keep up with recording logins fast enough in the event log.

I suggest you clean up your event log, turn down the number of things recorded, create a seperate application pool for DNN, and tweak the setting of that pool a tiny bit to allow more memory usage and faster cleanup. But, be careful with the settings, as there are a couple of them (like number of worker threads) that will wreak havoc with DNN. 

I'd have to load up the code to be ultimately sure but it goes like this:

All DNN roles are loaded into an array
All the DNN roles the user belongs to are loaded into an array
The AD roles the user belongs to are loaded into an array

A loop is done between the DNN  roles the user belongs and the AD roles to verify that the user should still be in the matching DNN roles.
A loop is done between all the DNN roles and the AD roles the user belongs to to make sure the user hasn't been added to any new roles.

Unfortunately there's no easy way to signify whether a DNN role is there to act as an AD role or not so I'm forced to pull all roles. I'm always looking for faster ways to do this but I don't know if I'm going to find one and I pretty sure that's the reason why Tam (the original author of the AD authentication) only sync'd on the very first login by a user.