HP Serviceguard Toolkit for NFS manual SG NFS Servers over VxFS High Availability

The files and filesystems can be shared and accessed concurrently within the cluster. However, file sharing and access from outside the cluster will still require NFS - client systems which are not members of the CFS cluster will use NFS to access the shared filesystems.

Cross mounting (with the nfs_xmnt script) is not needed since you can use CFS to share files and filesystems within the cluster.

Figures 2 and 3 also show how files and filesystems are accessed differently in a CFS environment versus a non-CFS environment. In a non-CFS environment, clients must access the server which exports a specific filesystem. In a CFS environment, clients can access the cluster via a load balancer or another mechanism such as a DNS round-robin scheme (represented by the cloud in Figure 3). Each NFS client can be directed to the server which currently has the most capacity available. This approach has a limitation that clients are bound to a particular NFS server when they issue the mount command.

Note: The implementation of a load balancer or DNS round-robin scheme is optional and is beyond the scope of this white paper. For more information about DNS round- robin addressing refer to the BIND Name Service Overview section in the HP-UX IP Address and Client Administrator’s Guide.

NFS

Client1

NFS

Client2

NFS

Client3

	Serviceguard NFS servers
NFS Server1		NFS Server2	NFS Server3
/VxFS1		/VxFS2	/VxFS3

Shared Storage /VxFS1/VxFS2/VxFS3

Figure 2. SG NFS Servers over VxFS – High Availability

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