pNFS support began in clustered Data ONTAP 8.1 for files only and continues with enhancements in clustered Data ONTAP 8.2. There is no Data ONTAP 7G/7-Mode support for pNFS. Current client support for pNFS is very limited, but NetApp does support all clients that support pNFS and follow the RFC specifications. By default the pNFS option is enabled, but it is only active if NFSv4.0 and NFSv4.1 support also are enabled. NetApp does not currently recommend pNFS for metadata-heavy workloads. pNFS requires a client that also supports pNFS. Currently, RHEL 6.4 is the only commercial Linux distribution that has full pNFS support. Check the link for more info "http://www.cptech.com/wp-content/uploads/2014/06/Clustered-Data-on-Tap.pdf"
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