Hi all, I am facing facing performance issues with our web servers which is working for concurrent 250 requests properly and then stops responding when the requests are more than 250 . The current configuration parameters are as follows : apachectl -version Server version: Apache/2.0.52 Server built: Jan 30 2007 09:56:16 Kernel : 2.6.9-55.ELsmp #1 SMP Fri Apr 20 16:36:54 EDT 2007 x86_64 x86_64 x86_64 GNU/Linux Server Hardware : MAIN MEMORY (i) Memory Size 4 GB Dual-Core Intel 5160 processors. httpd.conf Timeout 300 KeepAlive On MaxKeepAliveRequests 1000 KeepAliveTimeout 150 ## Server-Pool Size Regulation (MPM specific) # prefork MPM # StartServers: number of server processes to start # MinSpareServers: minimum number of server processes which are kept spare # MaxSpareServers: maximum number of server processes which are kept spare # ServerLimit: maximum value for MaxClients for the lifetime of the server # MaxClients: maximum number of server processes allowed to start # MaxRequestsPerChild: maximum number of requests a server process serves <IfModule prefork.c> StartServers 8 MinSpareServers 5 MaxSpareServers 20 ServerLimit 251 MaxClients 251 MaxRequestsPerChild 4000 </IfModule> # worker MPM # StartServers: initial number of server processes to start # MaxClients: maximum number of simultaneous client connections # MinSpareThreads: minimum number of worker threads which are kept spare # MaxSpareThreads: maximum number of worker threads which are kept spare # ThreadsPerChild: constant number of worker threads in each server process # MaxRequestsPerChild: maximum number of requests a server process serves <IfModule worker.c> StartServers 2 MaxClients 150 MinSpareThreads 25 MaxSpareThreads 75 ThreadsPerChild 25 MaxRequestsPerChild 0 </IfModule> I want to know about the difference between worker MPM and Prefork MPM , how to find out which one will be used by my apache server and the recommended one for highly loaded server.If some one provide me the link that best explains above two comparison also be very use full. Can any one guide me tuning to be done for the maximum utilization of the Resources and better performance of the Servers. Regards, lingu