as summ.
CHANGE: http://review.gluster.com/2614 (Introduce new extended attribute: node-uuid) merged in master by Vijay Bellur (vijay)
On the mount point if you get xattr for node-uuid you will get the glusterd uuid of the brick in which that file is present in the backend of the distributed setup . Command - getattr -n trusted.glusterfs.node-uuid <filename>