Re: Overwhelming a Web Application Server

[Thorbjoern Ravn Andersen <ravn@xxxxxxxxxx>]

Nathan Andelin skrev:
> At the stroke of midnight, one of our state universities opens their course registration system to the Internet, and within a matter of minutes the entire system slows to a snail's pace as eager students flood servers with course registration queries & requests for fall classes.
>
> The problem with an overwhelmed system is that nobody gets anything done under the burden of resource contention. Is anyone dealing with problems like this?  What stragegies work? Restricting Apache ThreadsPerChild? Reducing the KeepAliveTimeout?  Configuring session limits?
>   
I can strongly recommend Michael Nygards "Release It!" 
(http://www.michaelnygard.com/) which deals with these kinds of 
going-live issues.  Predicting them, simulating them properly, handling 
them.

http://www.pragprog.com/titles/mnee/release-it

In the concrete case the problem you must identify first is what is the 
bottleneck.  Frequently it is too many idle sessions which must time out 
to be reclaimed.  First try lowering the session timeout value.   Then 
investigate how your software doing actual work keeps track of sessions 
since this is most likely the next point you will have to investigate.

Can you profile the server?