NetWorker: Unable to mount ddboost device Err: 5034-nfs setattr failed

NetWorker fails to mount ddboost device.
NetWorker shows the following error:

ddboost_api ERROR: ddp_utime() failed, Path //<networker-server-name>/<device-name>/volhdr, Err: 5034-nfs setattr failed (nfs: Permission denied).

The following error can also be observed within ddfs.info:

(tid 0x7f2c82c04990): ddboost-<networker-server-name-62344>: ddboost_api ERROR: ddp_utime() failed, Path //<networker-server-name>/<device-name>/volhdr, Err: 5034-nfs setattr failed (nfs: Permission denied)

NetWorker MTree /data/col1/<networker-server-name> had Retention-Lock Governance enabled then disabled.
For example:

mtree list

Name                       Pre-Comp (GiB)   Status

------------------------   --------------   -------

/data/col1/<networker-server-name> 25280.9   RW/RLGD

------------------------   --------------   -------

RLGD : Retention-Lock Governance Disabled

When a DD file has "Retention-Lock Governance" enabled and disabled, it can only be deleted but not modified.
The NetWorker mount device operation requires to modify the device control file attribute (nfs setattr).

Users can run this with the following DDOS commands.

Create a new MTree: 

mtree create /data/col1/<new-mtree-name>

Fast copy NetWorker ddboost storage unit to the new MTree:

filesys fastcopy source /data/col1/<nw-server-name> destination /data/col1/<new-mtree-name>

Verify if fast copy is successful. If yes, the Pre-Comp (GiB) would be the same. If no, repeat step 1, 2 until successful or contact the Data Domain Support Team):

mtree list

Rename the NetWorker ddboost storage unit to another name:

ddboost storage-unit rename <nw-server-name> <another-name>

If rename fails, delete NetWorker ddboost storage unit, run Data Domain FIle System (DDFS) clean for a few seconds, then stop DDFS clean.

ddboost storage-unit delete <nw-server-name>

filesys clean start

filesys clean stop

Verify if NetWorker storage unit name is no longer used (if yes, <nw-server-name> would not display).

ddboost storage-unit show

Rename the new MTree to <nw-server-name>:

mtree rename /data/col1/<new-mtree-name> /data/col1/<nw-server-name>

Assign ddboost user to /data/col1/<nw-server-name>:

ddboost storage-unit modify <nw-server-name> user <ddboost-user>

Verify if the NetWorker storage unit name <nw-server-name> displays:

ddboost storage-unit show

Retry mount in NetWorker.

For Redfish Lifecycle Events (RLCE), users may not modify or delete the concerned ddboost-storage unit or MTree. You must start step 1 instead by creating a new ddboost storage-unit and then fast copying to the new underlying MTree.