Verifying the use of Oracle Direct NFS client

1) If dNFS is enabled, the alert.log will show the following entry when the database is started.

Oracle instance running with ODM: Oracle Direct NFS ODM Library Version 4.0

2) Query the dNFS server information from v$dnfs_servers view inside the database.

SQL> select svrname, dirname, mntport, nfsport, wtmax, rtmax from v$dnfs_servers;

SVRNAME            DIRNAME                 MNTPORT    NFSPORT      WTMAX      RTMAX
------------------ -------------------- ---------- ---------- ---------- ----------
fb-dnfs-test-02    /rman01                    2049       2049     524288      524288

Note: Even though dNFS is enabled, Oracle only mounts the volume/filesystem and opens the files when they are accessed. If no data files are accessed, then the above view will return no rows.

Troubleshooting oranfstab issues

Please make sure the svrname from the v$dnfs_servers show the server name from the oranfstab file. If not, generally there is some misconfiguration in the oranfstab file. Look for any dangling entries, lack of space after the keywords and clean up.

For example, in the following output the SVRNAME is not correct as it should be the actual server name from the oranfstab for all the exports under the given server but we see the IP addresses of the paths. This means the oranfstab is not configured correctly.

SQL> SELECT svrname, dirname, mntport, nfsport, wtmax, rtmax FROM v$dnfs_servers;

Server                    Export Name                                                         MNTPORT    NFSPORT      WTMAX      RTMAX  
------------------------- ---------------------------------------------------------------- ---------- ---------- ---------- ----------  
192.168.20.100            /oradata01                                                             2049       2049     524288     524288  
192.168.20.101            /oradata02                                                             2049       2049     524288     524288 
192.168.20.102            /redo01                                                                2049       2049     524288     524288  

Looking at the oranfstab file, we see the following.

server: fb-dnfs-01
local: 192.168.20.50
path: 192.168.20.100
local: 192.168.20.50
path: 192.168.20.101
local: 192.168.20.50
path: 192.168.20.102
local: 192.168.20.50
nfs_version: nfsv3
export: /oradata01 mount: /u02
export: /oradata02 mount: /u03
export: /redo01    mount: /u04

After rearranging them and removing the dangling local entry from the oranfstab file and restarting the database shows the expected output.

server: fb-dnfs-01
local: 192.168.20.50 path: 192.168.20.100
local: 192.168.20.50 path: 192.168.20.101
local: 192.168.20.50 path: 192.168.20.102

nfs_version: nfsv3
export: /oradata01 mount: /u02
export: /oradata02 mount: /u03
export: /redo01    mount: /u04

SQL> SELECT svrname, dirname, mntport, nfsport, wtmax, rtmax FROM v$dnfs_servers;

Server                    Export Name                                                         MNTPORT    NFSPORT      WTMAX      RTMAX 
------------------------- ---------------------------------------------------------------- ---------- ---------- ---------- ---------- 
fb-dnfs-01                /oradata01                                                             2049       2049     524288     524288  
fb-dnfs-01                /oradata02                                                             2049       2049     524288     524288
fb-dnfs-01                /redo01                                                                2049       2049     524288     524288

Oracle Direct NFS (dNFS) is the NFS client functionality directly integrated into the Oracle RDBMS server. Oracle dNFS makes the task of configuring an Oracle database on NAS storage like FlashBlade much simpler in comparison to Standard NFS (aka Kernel NFS).