ljain has worked on the JIRA:
HDFS-13052 to provide the possibility to make DistCP of SnapshotDiff with WebHDFSFileSystem. However, in the patch, there is no modification for the real java class which is used by launching the command "hadoop distcp ..."
You can check in the latest version here:
In the method "preSyncCheck" of the class "DistCpSync", we still check if the file system is DFS.
So I propose to change the class DistCpSync in order to take into consideration what was committed by Lokesh Jain.