A tech preview is available in Red Hat Enterprise Linux 6.2, introducing experimental client support for the protocol version NFSv4.1. A mandatory part of any NFSv4.1 implementation includes a number of incremental reliability and performance improvements. For example, all NFS traffic, including server-to-client callbacks, now share a single client-initiated TCP connection, allowing file delegations to operate through NAT and firewalls.
A major optional feature, pNFS, is included with NFSv4.1. When a server implements pNFS as well, a client is able to access data through multiple servers concurrently.
To use NFSv4.1, first create the /etc/modprobe.d/dist-nfs41.conf file with the command:
alias nfs-layouttype4-1 nfs_layout_nfsv41_files
Reboot, and then use the minorversion=1 mount option.
mount -o minorversion=1 server:/filesystem
No additional steps are needed to enable pNFS; if the server supports it, the client will automatically use it.
The protocol allows for three possible pNFS layout types: files, objects, and blocks. However the Red Hat Enterprise Linux 6.2 client only supports the files layout type, so will use pNFS only when the server also supports the files layout type.
