White Paper

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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.
/VxFS1
NFS Server1
/VxFS1
NFS Server2
/VxFS2
NFS Server3
/VxFS3
/VxFS2
NFS
Client3
Figure 2. SG NFS Servers over VxFS – High Availability
NFS
Client1
NFS
Client2
/VxFS3
Shared Storage
Serviceguard NFS servers