[Samba] samba share an NFS import?

[Jeremy Allison]

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.