samba - Aug 2012 - samba share an NFS import?

Is it a problem to share a folder via Samba that is actually an NFS import from
another machine?

Looking at Samba documentation, it seems it shouldn't be.  But I find only
this one reference to re-exporting an NFS import via Samba  (this is under
"Samba 3.6 Features added/changed"):

http://wiki.samba.org/index.php/Samba_3.6_Features_added/changed#NFS_quota_backend_on_Linux

which says "A new nfs quota backend for Linux has been added that is based
on the existing Solaris/FreeBSD implementation. This allows samba to communicate
correct diskfree information for nfs imports that are re-exported as samba
shares."

But googling the problem, I find numerous discussions, where most contain
something along the lines of this:

http://serverfault.com/questions/68330/samba-sharing-an-nfs-mount-point


which says, "The Samba manual mentions that re-exporting a NFS mountpoint
over Samba does not work correctly. NFS is not 100% POSIX compatible, so some
things work differently than what Samba expects.  I.e. you should run Samba on
the same server where you run the NFS service, exporting the local disks
directly."

I also came across various folks claiming one needs to play with the timing
parameters in smb.conf.

We're currently running Samba 3.5.10, under RHEL 6.2 (3.5.10 is the version
currently supplied with RHEL 6.2).  Machine Q nfs-mounts machine M's data
disks, and re-exports them via Samba for users to access.  We are experiencing
problems with the NFS share occasionally becoming very slow (both for machine Q
and the machines that mount them via Samba), and I'm wondering if the
re-export is the problem.

Question 1:  When was samba re-export of NFS import considered stable?  I.e., Do
I need to update to 3.6 (move ahead of RHEL distribution) for this to be OK?
Question 2:  Can someone point me to more official Samba documentation on
exporting?

On Fri, Aug 31, 2012 at 08:45:28PM +0000, Scott-Fleming, Ian
wrote:
> Is it a problem to share a folder via Samba that is actually an NFS import
from another machine?
> 
> Looking at Samba documentation, it seems it shouldn't be.  But I find
only this one reference to re-exporting an NFS import via Samba  (this is under
"Samba 3.6 Features added/changed"):
> 
>
http://wiki.samba.org/index.php/Samba_3.6_Features_added/changed#NFS_quota_backend_on_Linux
> 
> which says "A new nfs quota backend for Linux has been added that is
based on the existing Solaris/FreeBSD implementation. This allows samba to
communicate correct diskfree information for nfs imports that are re-exported as
samba shares."
> 
> But googling the problem, I find numerous discussions, where most contain
something along the lines of this:
> 
> http://serverfault.com/questions/68330/samba-sharing-an-nfs-mount-point
> 
> 
> which says, "The Samba manual mentions that re-exporting a NFS
mountpoint over Samba does not work correctly. NFS is not 100% POSIX compatible,
so some things work differently than what Samba expects.  I.e. you should run
Samba on the same server where you run the NFS service, exporting the local
disks directly."
> 
> I also came across various folks claiming one needs to play with the timing
parameters in smb.conf.
> 
> We're currently running Samba 3.5.10, under RHEL 6.2 (3.5.10 is the
version currently supplied with RHEL 6.2).  Machine Q nfs-mounts machine M's
data disks, and re-exports them via Samba for users to access.  We are
experiencing problems with the NFS share occasionally becoming very slow (both
for machine Q and the machines that mount them via Samba), and I'm wondering
if the re-export is the problem.
> 
> Question 1:  When was samba re-export of NFS import considered stable? 
I.e., Do I need to update to 3.6 (move ahead of RHEL distribution) for this to
be OK?
> Question 2:  Can someone point me to more official Samba documentation on
exporting?
Bottom line - it'll mostly work.

Caveat. Don't come complaining here when the locking doesn't work :-).

Jeremy.