Resolution:
If you enable Direct Data Transfer and you write a script that instantiates multiple Drivers from the same driver.properties file with the same port number, the first Driver will open a web server listening to the defined socket. Subsequent Drivers will not open another web server as long as the first Service is running, but will be able to continue running by using the first Service's server for direct data. However when the first Service completes, its server will be terminated, causing subsequent Services to fail.

If you write a shell script to create Services, each with their own Driver running from its own Java VM, your script must provide a different port number for the DSWebserverPort property normally set in the driver.properties file. To write a shell script for this situation, you could remove the DSWebserverPort property from the driver.properties file and set a unique port number for each Service using a command line property.

Also, more than one Driver cannot share the same GridCache directory. If you script multiple Drivers to run from the same driver.properties file, you will need to set a different DSCacheRootDirectory property for each Driver.