This statistic shows access per second to the file system during NDMP backup or restore. This statistic is only meaningful for tar-based backups because they occur at the file, and not block, level.
When to Check NDMP File System Operations
This could be useful to check when investigating the source of ZFS load. First, check all other sources of file system activity via the Protocol statistics. Also see the advanced Analytics statistics Data Movement: NDMP Bytes Transferred to/from Disk and Data Movement: NDMP Bytes Transferred to/from Tape.
NDMP File System Operations Breakdowns