Update intro with note on NFS potential single point of failure

doc/administration/high_availability/nfs_host_client_setup.md

 ### Configuring NFS for GitLab HA
 
-Setting up NFS for a GitLab HA setup allows all applications nodes in a cluster to share the same files and maintain data consistency. Application nodes in an HA setup act as clients while the NFS server plays host.
+Setting up NFS for a GitLab HA setup allows all applications nodes in a cluster 
+to share the same files and maintain data consistency. Application nodes in an HA
+setup act as clients while the NFS server plays host.
 
-Below are instructions for setting up an application node(client) in an HA cluster to read from and write to a central NFS server(host).
+> Note: The instructions provided in this documentation allow for setting a quick
+proof of concept but will leave NFS as potential single point of failure and 
+therefore not recommended for use in porduction. Explore options such as [Pacemaker 
+and Corosync](http://clusterlabs.org/) for highly available NFS in production.
+
+Below are instructions for setting up an application node(client) in an HA cluster
+to read from and write to a central NFS server(host).
 
 #### Step 1 - Install NFS Server on Host