Exporting a GPFS file system using NFS

To export a GPFS™ file system:

Create and mount the GPFS file system. In the examples, we assume a file system with a local mount point of /gpfs.
For performance reasons, some NFS implementations cache file information on the client. Some of the information (for example, file state information such as file size and timestamp) is not kept up-to-date in this cache. The client may view stale inode data (on ls -l, for example) if exporting a GPFS file system with NFS.

If this is not acceptable for a given installation, caching can be turned off by mounting the file system on the client using the appropriate operating system mount option (for example, -o noac on Linux NFS clients). Turning off NFS caching results in extra file systems operations to GPFS, and negatively affect its performance.
Note:
- Ensure that all GPFS file systems that you use to export data via NFS are mounted with the syncnfs option to prevent clients from running into data integrity issues during failover. Prior to mounting a GPFS system, it is a good practice to run the mmchfs command to set the syncnfs option, -o syncnfs.
- Ensure that NFS clients mount with the -o sync and -o hard options to prevent clients from running into data integrity issues during failover.
Make sure that the clocks of all nodes in the GPFS cluster are synchronized. If this is not done, NFS access to the data, as well as other GPFS file system operations, may be disrupted.
NFS relies on metadata timestamps to validate the local operating system cache. If the same directory is either NFS-exported from more than one node, or is accessed with both the NFS and GPFS mount point, it is critical that clocks on all nodes that access the file system (GPFS nodes and NFS clients) are constantly synchronized using appropriate software (for example, NTP). Failure to do so may result in stale information seen on the NFS clients.
Ensure that NFS is properly configured and running.
For Linux nodes, information on configuring NFS can be obtained at the linuxdocs.org website.

For AIX® nodes, refer to AIX in IBM® Knowledge Center for information about configuring NFS.
Use the mmnfs export add, mmnfs export change, or mmnfs export remove command as required.
Note: For IBM Spectrum Scale™ exports, you must use mmnfs export add, mmnfs export change, or mmnfs export remove command. Editing the /etc/exports file to specify file systems to be exported does not work for IBM Spectrum Scale exports; this can only be used for exports that are not IBM Spectrum Scale exports.