Running Oracle Weblogic Server on Linux ? Did you check Entropy

This post covers performance issue (Admin Console taking ages while accessing) and is must read if you are running WebLogic Server on Linux.

We encountered this issue while managing Fusion Middleware (with WebLogic) for one of our customer where accessing Admin Console was very Slow and there were no errors in log (memory and CPU were just fine).

A Brief decsription about Entropy on linux Platform:

An Operating System performs cryptographic operations at every time (on ssh challenges, https connections, etc.) .
Linux has two devices to provide random data at any time: /dev/random and /dev/urandom so the /dev/random pool gets consumed quite fast with the cryptographic operations. This pool also gets consumed while performing I/O operations, mouse,keyboard etc. and since, the Java uses /dev/random by default as entropy generator device that runs out of random bits and Therefore, makes us waiting for more time.

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After starting the WebLogic server instance the available Entropy on the system was substantially decreasing.

Check the default system entropy using the command below:
# cat /proc/sys/kernel/random/poolsize

Check the available entropy using th command below:
# cat /proc/sys/kernel/random/entropy_avail


1. Temporary Fix:

a. Override the JAVA_OPTIONS environment variable before starting WebLogic Server via shell scripts (./


b. Start Weblogic server instance


2. Permanent Fix:

a. Edit the Java Security Properties file located in $JAVA_HOME/jre/lib/security/ and change the securerandom.source property which points to /dev/random (by default). set it as:


b. Save the changes and Start WebLogic server


If you want to learn more issues like above or wish to discuss challenges you are hitting in Oracle Weblogic Server, register for our Oracle Weblogic Administration Training.

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