In Oracle 11g a native NFS client has been placed in Oracle Database kernel.  It improves performance when Network File Systems are in use.  Oracle NFS kernel optimizes and eliminates overhead of NFS, eliminating the need to tune NFS parameters at OS layer.

 

To use Direct NFS, the NFS file system must be mount and available by OS kernel .  The Oracle Direct NFS Client manages Oracles access to drives, by a configuration file call orafstab or mount tab file /etc/mtab on linux.  The file $ORACLE_HOME/dbs/orafstab would specify the direct NFS client settings for a single database.  Oracle looks for settings in /etc/oranfstab then Oracle reads /etc/mtab to identify available NFS mounts.

 

To use Direct NFS mount setting you have to replace standard Oracle Disk Manager (ODM) library with one supporting Direct NFS Client.

 

Example

 

[oracle@linux2 ~]$ $ORACLE_HOME/dbs/orafstab

server: MyNFSServer1

path: 192.168.1.1

path: 192.168.1.2

path: 192.168.1.3

path: 192.168.1.4

export: /vol/ oradata1

mount: /mnt/ oradata1

 

Once the file exists, the following commands will enable the Direct NFS Client ODM Library

 

[oracle@linux2 ~]$ cd $ ORACLE_HOME/ lib

[oracle@linux2 ~]$ cp libodm11. so libodm11. so_stub

[oracle@linux2 ~]$ ln –s libnfsodm11. so libodm11. so

 

 

 

Larry Catt

OCP