[Plug-in] Tuning IBM HTTP Server to maximize the number of client connections to WebSphere Application Server

Tuning IBM HTTP Server to maximize the number of client connections to WebSphere Application Server

Problem(Abstract)

Out of the box, IBM HTTP Server supports a maximum of 600 concurrent connections. Performance will suffer if load dictates more concurrent connections, as incoming requests will be queued up by the host operating system.

You can increase the number of maximum connections allowed by IBM HTTP Server by editing the httpd.conf file.

Resolving the problem

First and foremost, you must determine the maximum number of simultaneous connections required for this Web server. Using mod_status or mod_mpmstats (available with ihsdiag) to display the active number of threads throughout the day will provide some starting data.

There are 3 critical aspects to MPM (Multi-processing Module) tuning in IBM HTTP Server.

1. Configuring the maximum number of simultaneous connections (MaxClientsdirective)


2. Configuring the maximum number of IBM HTTP Server child processes (ThreadsPerChilddirective)


3. Less importantly, configuring the ramp-up and ramp-down of IBM HTTP Server child processes (MinSpareThreads, MaxSpareThreads, StartServers)