SDC does not start with error message: Conflicting collector combinations in option list; please refer to the release notes for the combinations allowed.

Conflicting collector combinations in option list; please refer to the release notes for the combinations allowed

Error: Could not create the Java Virtual Machine.

Error: A fatal exception has occurred. Program will exit.

This error occurs when the JVM is started with conflicting garbage collector command line arguments.  Data Collector does not start at all, there is no information in sdc.log -  the errors above come out on stderr. 

In one specific case, the customer’s environment specified:

SDC_JAVA_OPTS='-Xmx3g -Xms3g -XX:+UseG1GC’

Then SDC startup script exported:

SDC_JAVA8_OPTS='-XX:+UseConcMarkSweepGC -XX:+UseParNewGC'

Both sets of options were provided to the JVM which could not start due to the conflict.

To solve this remove one set of GC options.  One way is to replace SDC_JAVA8_OPTS with the customer's custom GC options.