I have a DNN 4.5.3 application that is running on a top end PowerDNN server. Quad Xeon with 4GB RAM. It is a relatively simple application where school people (admin, teachers, students) are presented with a round of questions they must answer. The Assessment Administrators (my clients) use the information gained to evaluate the schools and help them understand where they are strong and where they are weak and how they can get better. A worthy goal. You can see the UI here.
http://www.blueribbonschools.com/assessmentscreenshot.jpg
It is AJAX enabled and only pulls back the necessary question info each time. The records already exist in the db and we just update the Mark for Review and AnswerID each time based n their participant login id.
Today, we ramped up to nearly 60 participants on the on the assessment application over a few minutes. It took some about 15 minutes to answer all 71 questions and some it took almost 30 minutes. Here are some results.
There was a good bit of the time when the Processor usage was peaking at or near 100%. I was watching the event logs and the only issues were these scheduler errors that only occurred during the assessment. We got about 5 of them. We have Users Online set at 10 minutes so that we can have an idea of how many are online at any time. Could that be causing the scheduler issue?
InnerException: Add failed. Duplicate key value supplied.
FileName:
FileLineNumber: -1
FileColumnNumber: -1
Method:
StackTrace:
Message: System.ArgumentException: Add failed. Duplicate key value supplied. at Microsoft.VisualBasic.Collection.Add(Object Item, String Key, Object Before, Object After) at DotNetNuke.Services.Scheduling.DNNScheduling.Scheduler.CoreScheduler.AddToScheduleInProgress(ScheduleHistoryItem objScheduleHistoryItem) at DotNetNuke.Services.Scheduling.DNNScheduling.Scheduler.CoreScheduler.WorkStarted(SchedulerClient& objSchedulerClient)
The SQL Server 2005 (NOT Express) ramped up steadily to 1.2GB of memory and the processor usage attributed to the SQL Server was between 2% and 30%
The w3wp.exe NETWORK SERVICE process only ramped up to about 165MB and the processor usage attributed to the Website was between 30% and 79%.
So adding the two processes together...we were peaking around 100%. But is was up and down. It never seemed to stay at or near 100% for more than a couple of seconds.
So we topped out at about 1/2 of the total RAM in the box. Here are some of my questions for the DNN gurus out there.
Keep in mind that the only other thing running on this server is the main website for my client at www.blueribbonschools.com which is not getting a significant amount of traffic.
Why would the server be so strained at 100% CPU (all 4 CPUs were tracking together)? Is it normal for the processor to just give all it has when a decent traffic load is presented?
If we put 100 participants on the server, would it still just peak out at 100% occasionally but still work well? During the peak load, I logged in and answered about 17 questions over a few minutes and the UI was very responsive. So even though it was peaking at 100%, there were no complaints about the site.
If we put in many more concurrent participants, should we expect it to still handle the load, but possibly just be a little slower on UI responsiveness?
It has been about 7 hours since the test and SQL Server process still shows 1.2GB of memory. I thought that out of the box SQL Server 2005 would ramp up and down on memory and deallocate it when it was not needed? Is there some setting that I should use to make that work or should I restart the SQL Server service? Or is it better to already have memory allocated to the SQL process and then if it grows beyond that it can add more?
Where will the SQL Server service crash from a memory perspective since there are 4GB available? If SQL Server does crash, does it typically restart the service and keep going?
We are starting with some real assessments on Friday with the bulk of them next week at 7 schools. So we could have lots of times with close to 100 participants online at any time. I am just trying to see if there are any last minute tweaks I should make to try to minimize issues.
Thanks so much to DNN Core team for giving us a great product and thanks in advance to any Gurus that can help me make this app as good as it can be for my clients.