Mounting shared devices and using the /etc/fstab file

Mounting shared devices can be done from the ocfs2console, or from the command line.

The shared disks must be mounted on each node individually, but it is not necessary for all the disks to be mounted on all the nodes. If a particular node does not need access to a particular disk, there is no need to have that disk mounted on that node. When disks are mounted on multiple nodes, you can verify the shared file behavior by creating a file with an editor and saving it, which makes it immediately visible from any of the nodes.

The following example, from file /etc/fstab, shows the required mount options for OCFS2 disks that will be mounted at system restart time. The first device, /dev/dasdf1 is a partitioned data disk. The second device, /dev/dasdd1, is for disks that are shared sources of binary executables.

Issue this command:

cat /etc/fstab

The output is similar to these lines:

 /dev/dasdf1 /datadisk1 ocfs2   _netdev,datavolume,nointr  0     0
 /dev/dasdd1 /bin_disk  ocfs2   _netdev                    0     0

The mounting options from the cat /etc/fstab command output are defined in the following list:

_netdev: Ensures that the OCFS2 volume is not mounted before the networking structure is up, and ensures that there is an unmount before shutting down the network.
datavolume: Applies only to data volumes, and every type of file usage except shared binaries. On a clustered database such as Oracle Real Application Clusters (RAC), the datavolume includes the Cluster Registry and Voting Disks. The datavolume allows direct I/O access to the files.
nointr: Prohibits interrupts, and is applied to the same type of data files as the datavolume option.

When Oracle RAC Voting Disks, and OCR (Oracle Cluster Registry) disks are installed on OCFS2, the disks require the same mounting options as datavolumes: _netdev, datavolume, nointr.