Follow these instructions to configure memory overload protection from the administrative
console.
About this task
To protect against memory overload, the memory overload protection must initially discover
the maximum rate, that is, calls per second, that can be sustained without exceeding the maximum
percentage of the maximum heap size. As it is discovering the maximum rate, memory overload
protection slowly allows more traffic through without affinity, but will reject the remainder.
Initially, a potentially large number of HTTP requests or SIP messages without affinity will be
rejected with a 503 (unless the error code is changed).
Intelligent Management persists the maximum rate across server restarts, so
it must discover the maximum rate once. The maximum rate can change over time due to changes in the
session or dialog lifetimes, but these lifetimes generally change relatively slowly and memory
overload protection is able to react to such changes. When discovering the maximum rate,
Intelligent Management must keep the rate relatively steady for at least an
averaging window. The averaging window must be at least as long as the lifetime of most of the HTTP
sessions, SIP dialogs, or application sessions. Therefore, the longer the averaging window, the
longer it will take to start.
Memory overload protection is disabled by default. Memory overload
protection is enabled when the memory overload protection (MOP) value is set to less than 100.
Avoid trouble: To ensure that the memory overload protection is configured
properly, the
-agentlib parameter needs to be set in the
Generic JVM
arguments field. Specifying the
-agentlib parameter is only required in
WebSphere® Application Server Version 8.5.5.2 and
earlier. For a version of WebSphere Application Server
after version 8.5.5.2, the
-agentlib parameter is always loaded and does not need
to be set, even if the autonomic request flow manager (ARFM) is disabled.
gotcha
To enable,
follow these steps from the administrative console: