3.7.0 HP StorageWorks HP Scalable NAS File Serving Software administration guide - HP Scalable NAS 3.7 for Linux (AG513-96002, October 2009)

Considerations for ensuring data safety
NFS write performance and the risk of data loss during NFS write operations are
affected by the use of the sync and async options. In your configuration, you will
need to determine whether the following should be synchronous or asynchronous:
• The PSFS filesystem mount
• The server export of the PSFS filesystem
• The client mount of the exported data
For the least risk of data loss during NFS operations, use the sync option for all of
these components. Keep in mind however, that when sync is used, NFS performance
can be slow because each write must be committed. As an alternative, you may
prefer to use the sync option only for server exports.
The async option provides better NFS write performance, as it allows writes to be
acknowledged before being committed on disk; however, it gives less coherency
with regard to on-disk contents in the cluster. Consequently, server crashes can lead
to silent-data-loss; the NFS client may never be aware of a given server crashing
because FS Option provides for seamless fail-over.
Add an Export Group
To create an Export Group, select Cluster > Add > Add Export Group. You can also
right-click on an existing Virtual NFS Service that is not currently assigned to an
Export Group and select Add Export Group.
Configure FS Option for Linux166