NFS writes and ZFS

[John Nielsen]

I have a FreeBSD server (which I use as a NAS device, among other things) 
and a FreeBSD deskop. The desktop is running 7-STABLE from a couple days 
ago and the server is running 8-CURRENT from yesterday. The server has 
several NFS-exported ZFS'es which I mount from the desktop. Since moving 
the shares to ZFS I've been having trouble writing to them from the 
desktop--the mount hangs after the first or second attempt. This is 
similar if not identical to what's described in the thread 
(from -current) I partially copied below.

Today I discovered that the problem seems to go away if I change the NFS 
mount options on the desktop. The following is a summary/timeline of what 
I've tried:

7-STABLE client, no NFS options (defaults); 7-STABLE server, UFS; works
7-STABLE client, no NFS options (defaults); 7-STABLE server, ZFS; broken
7-STABLE client, no NFS options (defaults); 8-CURRENT server, ZFS; broken
7-STABLE client, tcp,nfsv3,-r32768,-w32768; 8-CURRENT server, ZFS, works

My litmus test is to run fetch in the NFS directory a couple times since 
in my typical usage the failure is most apparent when fetching distfiles 
to the shared ports tree.

I didn't do a thorough search but I don't see any open PR's about this 
issue (though I remember the thread below and other discussions about the 
same time). Should I submit one?

Other than that I just wanted to report that 1) this is apparently (still) 
an issue and 2) the NFS flags above seem like a good workaround so far.

Thanks,

JN

> Newsgroups: muc.lists.freebsd.current
> From: d... at des.no (Dag-Erling Smørgrav)
> Date: Sun, 07 Oct 2007 10:48:49 +0200
> Local: Sun, Oct 7 2007 4:48 am
> Subject: Re: ZFS & NFS integration...
> 
> Darren Reed <darr... at freebsd.org> writes:
> > Dag-Erling Smørgrav wrote:
> > > Darren Reed <darr... at freebsd.org> writes:
> > > > Whats the planned status for ZFS+NFS with 7.0?
> > > Don't Do It, basically.
> > This sounds like a "shoot yourself in the foot" comment.
> 
> > Why?
> 
> I haven't figured out the exact details yet, but apparently when the
> client closes a file that was opened read / write, the server stops
> responding to that client.
> 
> DES