17 Avoiding JVM Delays Caused By Random Number Generation

This chapter describes how to avoid Java Virtual Machine (JVM) delays in Oracle Communications WebRTC Session Controller processes caused by random number generation.

Avoiding JVM Delays Caused by Random Number Generation

The library used for random number generation in Oracle's JVM relies on /dev/random by default for UNIX platforms. This can potentially block the WebRTC Session Controller process because on some operating systems /dev/random waits for a certain amount of "noise" to be generated on the host system before returning a result. Although /dev/random is more secure, Oracle recommends using /dev/urandom if the default JVM configuration delays WebRTC Session Controller startup.

To determine if your operating system exhibits this behavior, try displaying a portion of the file from a shell prompt:

head -n 1 /dev/random

If the command returns immediately, you can use /dev/random as the default generator for Oracle's JVM. If the command does not return immediately, use these steps to configure the JVM to use /dev/urandom:

1. Open the JAVA_HOME/jre/lib/security/java.security file in a text editor where JAVA_HOME is the location of your java installation.

2. Change the line:

   securerandom.source=file:/dev/random
   

   to read:

   securerandom.source=file:/dev/urandom
   

3. Save your change and exit the text editor.