NFSv4.1 server support for pNFS Flex File layouts


Linux Kernel Configuration
└─>File systems
└─>Network File Systems
└─>NFSv4.1 server support for pNFS Flex File layouts
In linux kernel since version 4.1 (release Date: 2015-06-21)  
This option enables support for the exporting pNFS Flex File
layouts in the kernel's NFS server. The pNFS Flex File layout
enables NFS clients to directly perform I/O to NFSv3 devices
accessible to both the server and the clients. See
draft-ietf-nfsv4-flex-files for more details.

Warning, this server implements the bare minimum functionality
to be a flex file server - it is for testing the client,
not for use in production.

If unsure, say N.