Backing up Oracle DBFS filesystem on Exadata

[good2bgold]

We have a 4 node Exadata system. The Oracle admins have created a DBFS (DataBase File System) that is shared among the nodes. They want to back this up. We were originally able to back it up, but only on the node that was used to create the file system.  That node was rebooted last week, and now we are not able to back it up at all.  The Oracle admin is fairly certain that it has something to do with how the file system is mounted, but he is not sure what to change. Does anyone have any experience with backing up a DBFS file system on an Exadata platform?

[good2bgold]

Forgot to add, the NetBackup system (master and media servers) are at 7.6.0.2.  The client installed on the Exadata nodes is 7.5.0.6.

[Michael_G_Ander]

Couple of questions

Do you get an error when attempting backup ?

Have you changed directory to under the mount point and tried to do a ls ?

[Nicolai]

Netbackup integration to Oracle is a media manager layer. The built-in backup tool in Oracle is RMAN

Try to run a RMAN backup of e.g. a control file to disk - it that fails you can exclude Netbackup of the equation.

[Yasuhisa_Ishika]

Your Oracle admin have forgoten how to mount DBFS on each nodes, right?

Command to mount DBFS is described in Oracle's manual.

https://docs.oracle.com/database/121/ADLOB/adlob_client.htm#ADLOB46191

[Marianne]

The config almost sounds like RAC configuration...

Maybe go through the RAC chapter in  NetBackup for Oracle Administrator's Guide  and see if it helps. 

[NBU_TSE]

Did you fail back the node?

Perhaps the active node is now the other node which may not have been properly configured

[good2bgold]

Have not worked on this since November. The user decided not to worry about backing up that area of the system. Thanks to all who posted suggestions - I appreciate the help!