Currently to use Hadoop with GlusterFS, the Hadoop Map/Reduce daemons viz. TaskTracker and JobTracker needs to run as super-user. This is needed to be able to mount/unmount GlusterFS volume and access/modify data in it. On the contrary using Hadoop with HDFS had no such limitation. The daemons can run as any user and have full permission of the FS.
The solution to the above case is solved by using Mounbroker. A detailed explanation of it's working in mentioned here https://gist.github.com/71ff8faa041425662185