Multiple Driver Instances

Services can fail if you enable Direct Data Transfer and write a script that instantiates multiple Drivers from the same driver.properties file with the same port number. The first Driver opens a web server listening to the defined socket. Subsequent Drivers do not open another web server as long as the first Service is running, but can continue running by using the first Service’s server for direct data. However, when the first Service completes, its server ends, causing subsequent Services to fail.

You can avoid this problem by writing a shell script to create Services, each with its 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 can remove the DSWebserverPort property from the driver.properties file and assign a unique port number for each iteration.

More than one Driver can share the same directory. However, if you do so you must set a unique DSCacheRootDirectory for each Driver if using GridCache. Also, if using long-running Services, you must set a unique DSWebServerDir property so that one Driver’s file cleaner does not clean another session’s initialization data.