Re: HELP: NFS mount hangs when attempting to copy file

[Trond Myklebust <trond.myklebust@fys.uio.no>]

on den 20.07.2005 Klokka 18:56 (-0400) skreiv Timothy Miller:
> My research suggests that NFS client mounting is kernel-based, so
> that's why I'm posting here.  If there's a more appropriate list to
> post to, I apologise, but I am not a list member.
> 
> I'm having a bit of a problem doing simple copies over an NFS mount. 
> The client is running Linux (2.6.11), and the server is running
> Solaris (5.8).
> 
> When I first boot the client, getting NFS directory listings works
> just fine.  But the instant I try to copy a file (to or from), the NFS
> mount hangs.  While I can still do other network activity (even rlogin
> to the server), any NFS access I try to do after that point hangs,
> including directory listings.
> 
> I have had this same client and server working flawlessly for years. 
> The only change is that the client is now on a VPN (Watchguard SOHO
> box).  However, I have a Sun machine on the same VPN network segment,
> and it can copy files with no problem, so it's not the router/SOHO
> that's blocking anything.  (NIS and DNS also work just fine for both
> machines.)

I beg to disagree. A lot of these VPN solutions are unfriendly to MTU
path discovery over UDP. Sun uses TCP by default when mounting NFS
partitions. Have you tried this on your Linux box?

Cheers,
  Trond

> Also, after it hangs like that, I cannot reboot the machine normally. 
> When attempting to unmount the network filesystems, the shutdown
> hangs, and I have to hard-reset the machine.
>  
> Is there anyone who could please help me to debug this problem?  As
> far as I know, I have NFS setup properly, but I don't know enough
> about it to know what options I might try.  I don't even care if the
> fix degrades performance; I just want it to not hang.
> 
> Does anyone have any ideas? 
>  
> Thanks very much in advance!
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