[Gluster-users] Some client problems with TCP-only NFS in Gluster 3.1

[Craig Carl]

Stephan - 
I missed that in the FAQ, thanks! I'll forward your comments to the engineering team that wrote gNFS, see what feedback I get. 

Craig 

--> 
Craig Carl 
Senior Systems Engineer 
Gluster 


From: "Stephan von Krawczynski" <skraw at ithnet.com> 
To: "Craig Carl" <craig at gluster.com> 
Cc: "Brent A Nelson" <brent at phys.ufl.edu>, gluster-users at gluster.org 
Sent: Friday, October 22, 2010 6:05:02 AM 
Subject: Re: [Gluster-users] Some client problems with TCP-only NFS in Gluster 3.1 

On Fri, 22 Oct 2010 04:46:44 -0500 (CDT) 
Craig Carl <craig at gluster.com> wrote: 

> {Resending due to incomplete response] 
> 
> Brent, 
> Thanks for your feedback . To mount with a Solaris client use - 
> ` mount -o proto=tcp,vers=3 nfs://<SERVER-ADDR>:38467/<EXPORT> <MNT-POINT>` 
> 
> As to UDP access we want to force users to use TCP. Everything about Gluster is designed to be fast , as NFS over UDP approaches line speed it becomes increasingly inefficient, [1] we want to avoid that. 
> 
> I have updated our documentation to reflect the required tcp option and Solaris instructions. 
> 
> [1] http://nfs.sourceforge.net/#faq_b10 

Sorry to jump in at this point. If you read the FAQ you may have noticed 
that the problem only hits very ancient boxes with kernels lower 2.4.20 (!). 

On contrary you gain a real problem with NFS over TCP if you are experiencing 
even very minor packet loss. Your tcp-based server comes to a crawl in such a 
scenario. In fact we completely dropped the idea of NFS over TCP exactly for 
that reason. We never experienced any performance problem with NFS over UDP. 

Regards, 
Stephan 

> 
> 
> Thanks again, 
> 
> Craig 
> 
> --> 
> Craig Carl 
> Senior Systems Engineer 
> Gluster 
> 
> 
> From: "Brent A Nelson" <brent at phys.ufl.edu> 
> To: gluster-users at gluster.org 
> Sent: Thursday, October 21, 2010 8:18:02 AM 
> Subject: [Gluster-users] Some client problems with TCP-only NFS in Gluster 3.1 
> 
> I see that the built-in NFS support registers mountd in portmap only with 
> tcp and not udp. While this makes sense for a TCP-only NFS 
> implementation, it does cause problems for some clients: 
> 
> Ubuntu 10.04 and 7.04 mount just fine. 
> 
> Ubuntu 8.04 gives "requested NFS version or transport protocol is not 
> supported", unless you specify "-o mountproto=tcp" as a mount option, in 
> which case it works just fine. 
> 
> Solaris 2.6 & 7 both give "RPC: Program not registered". Solaris 
> apparently doesn't support the mountproto=tcp option, so there doesn't 
> seem to be any way for Solaris clients to mount. 
> 
> There may be other clients that assume mountd will be contactable via 
> udp, even though they (otherwise) happily support TCP NFS... 
> 
> Thanks, 
> 
> Brent 
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