Home > Storage > PowerStore > Databases and Data Analytics > Dell PowerStore: Oracle Best Practices > Enabling and disabling Oracle dNFS
dNFS is enabled and disabled with the following commands from the Linux user owning the ORACLE_HOME.
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk dnfs_on
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk dnfs_off
If oranfstab does not exist, dNFS creates a single dNFS channel for entries found in /etc/mtab that are required for the running database. This single dNFS channel is used for both dNFS control and dNFS data traffic. The local IP address used for the dNFS channel is the IP address used to mount the NFS share. In Oracle, the dNFS channel has a name equal to the local IP address of the mount entry in /etc/mtab.
Note: If oranfstab is not used, dNFS load balancing and scaling are not available. For more information, see Benefits of using oranfstab.
Figure 73 shows the mount point, /etc/fstab, and /etc/mtab entries for the single NFS share used in this paper:
Figure 74 shows Oracle referring to the name (filer) of the single channel as the IP address used to mount the PowerStore NFS export. Because a local IP address is not defined, dNFS reports the local IP in the alert log as a null value. In this case, dNFS uses the IP address used to mount the NFS share for dNFS data traffic.
If multiple channels to a NAS server are needed for increased dNFS bandwidth, automatic dNFS data traffic load balancing, or automatic dNFS channel failover, the file oranfstab is required. dNFS automatically performs load balancing across all specified channels defined in oranfstab: if one channel fails, dNFS reissues I/O commands over any remaining available channel for that NAS server.
When oranfstab exists, dNFS control traffic uses the IP address used to mount the NFS share. dNFS data traffic is balanced across the local:path IP address mappings of the NAS server stanza specified in oranfstab to which the database belongs. local IP addresses are set to the IP address of the Ethernet interfaces on the database server that are to be used for the database. path IP addresses must be the IP addresses of the PowerStore NAS server bonded network interfaces.
A dNFS channel for each of the local:path IP address mappings is created in the database instance. For each channel, the value of the NAS server name in oranfstab is recorded in the dNFS channel metadata.
oranfstab may contain multiple NAS server stanzas.
The following oranfstab file defines one NAS server with two dNFS data paths:
Note: The format of specifying the dNFS data paths can vary within oranfstab. Also, if Kerberos is not used, the value of server can be any text. Dell Technologies recommends that the value of server be the name of the PowerStore NAS server for which the dNFS data paths defined in oranfstab apply.
The following oranfstab file contains two dNFS data paths to two NAS servers. Each NAS server services a different database.
When the Oracle instance is started, dNFS channels for the instance are created. The following example shows two channels for NAS server ORA-ASM-NFS. Channels for NAS server ORA-NAS01 are not shown because the current database relies only on ORA-ASM-NFS.