My desktop don't have an internal hard drive. I installed Ubuntu in a crappy old portable hard disk which is very slow. I mounted the home folder of my laptop to the desktop using NFS. My desktop and my laptop are directly connected using a gigabit connection. If I am correct any kind of caching on my local disk in desktop will only slow down the access.
So how can I make sure that none of the data from the NFS share is cached to my local drive.