NFS on 10G interfaces still painfully slow

[Alan Somers]

On Tue, Aug 2, 2016 at 2:49 AM, Gerrit Kühn <gerrit.kuehn at aei.mpg.de> wrote:
> Hi all,
>
> I already reported this issue here a year ago and unfortunately was not
> able to fix it back then. Now I had another run at it, using two recent
> 10.3-machines with a direct 10G link. I still see nfs is painfully
> slow (around 20-80MB/s). I tried both nfsv3 and nfsv4, with almost the same
> results. Everything I tried so far (mtu size, wcommitsize, readahead...)
> only makes things worse or at least not much better.
> Moving data in different ways (scp, ggate) is much faster, so plain
> network speed should not be an issue.
>
> Is there anyone around here who can confirm that nfs can go faster over
> 10G links?
> Any hints for further tuning/debugging are greatly appreciated.
>
>
> cu
>   Gerrit


I can get 1GB/s over NFS on a 10G link, so it's not always slow.
There's probably something about your setup that's slowing it down.
What is your NFS client?  If Linux, make sure that you're using the
"async" mount option instead of "sync".  What benchmark are you using
to measure that speed?  Did you remember to start lockd and statd?  If
you post your /etc/exports and the client's /etc/fstab, that might
reveal something.