[CentOS] CentOS7 and NFS

Tue May 12 14:10:49 UTC 2020
James Pearson <james-p at moving-picture.com>

Patrick Bégou wrote:
> 
> 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"...;-)

How many nfsd threads are you running on the server? - current count 
will be in /proc/fs/nfsd/threads

James Pearson