Low-Memory Situations

If Web Server must run in low-memory situations, reduce the thread limit to a bare minimum by lowering the value of the Maximum Threads setting on the configuration's Performance Tab ⇒ HTTP sub tab. You can also set it with wadm set-thread-pool-prop command's max-threads property.

Your web applications running under stress might sometimes result in the server running out of Java VM runtime heap space, as can be seen by java.lang.OutOfMemoryError messages in the server log file. There could be several reasons for this (such as excessive allocation of objects), but such behavior could affect performance. To address this problem, profile the application. Refer to the following HotSpot VM performance FAQ for tips on profiling allocations (objects and their sizes) of your application:

http://java.sun.com/docs/hotspot/index.html

At times your application could be running out of maximum sessions (as evidenced by a “too many active sessions” message in the server log file), which would result in the container throwing exceptions, which in turn impacts application performance. Consideration of session manager properties, session creation activity (note that JSPs have sessions enabled by default), and session idle time is needed to address this situation.