NDMP backup job on an Isilon filer fails with NDMP_ILLEGAL_ARGS_ERR (78900)

Date: Sep 2008
Product & Version: NVBU 8.x
OS Version: NA
Module & Version: NDMP 7.0.6
Application version:Isilon OneFS 4.7.1.8

Symptoms:

An NDMP backup of an Isilon filesystem fails with:
Error 2008/08/29 14:31:30 38 Data Plugin NETVAULT Failed to start backup: NDMP_ILLEGAL_ARGS_ERR

Check the path definition for the "Directory" field of the backup job, this should be a full mount point path, not just the filesystem path.
e.g. for a directory in the root ("/") called "data", the path for the backup job would be: "/ifs/data"
and NOT "/data"

Use the "mount" command to get the full mount point paths for non-root filesystems.