Hi, I need some help with NFSv4 setup/tuning. I have a dedicated nfs server (2 x E5-2620 8cores/16 threads each, 64GB RAM, 1x10Gb ethernet and 16x 8TB HDD) used by two servers and a small cluster (400 cores). All the servers are running CentOS 7, the cluster is running CentOS6. Time to time on the server I get: kernel: NFSD: client xxx.xxx.xxx.xxx testing state ID with incorrect client ID And the client xxx.xxx.xxx.xxx freeze whith: kernel: nfs: server xxxxx.legi.grenoble-inp.fr not responding, still trying kernel: nfs: server xxxxx.legi.grenoble-inp.fr OK kernel: nfs: server xxxxx.legi.grenoble-inp.fr not responding, still trying kernel: nfs: server xxxxx.legi.grenoble-inp.fr OK There is a discussion on RedHat7 support about this but only open to subscribers. Other searches with google do not provide useful information. Do you have an idea how to solve these freeze states ? More generally I would be really interested with some advice/tutorials to improve NFS performances in this dedicated context. There are so many [different] things about tuning NFS available on the web that I'm a little bit lost (the opposite of the previous question). So if some one has "the tutorial"...;-) Thanks Patrick