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Date: Thu, 19 Oct 2006 10:53:42 +0900 From: "Mohit Katiyar" <katiyar.mohit@...il.com> To: "Trond Myklebust" <trond.myklebust@....uio.no> Cc: "Frank van Maarseveen" <frankvm@...nkvm.com>, linux-kernel@...r.kernel.org, "Linux NFS mailing list" <nfs@...ts.sourceforge.net> Subject: Re: NFS inconsistent behaviour Yes, I do not want to mount unmount infinitely but was just checking out of curiosity but mounting/unmounting infinitely works comepletely fine on SLES 9 which uses 2.6.5 kernel. I was just wondering what has been changed that it does not work now? On 10/19/06, Trond Myklebust <trond.myklebust@....uio.no> wrote: > On Wed, 2006-10-18 at 08:39 +0200, Frank van Maarseveen wrote: > > On Wed, Oct 18, 2006 at 10:22:44AM +0900, Mohit Katiyar wrote: > > > I checked it today and when i issued the netstat -t ,I could see a lot > > > of tcp connections in TIME_WAIT state. > > > Is this a normal behaviour? > > > > yes... but see below > > > > > So we cannot mount and umount infinitely > > > with tcp option? Why there are so many connections in waiting state? > > > > I think it's called the 2MSL wait: there may be TCP segments on the > > wire which (in theory) could disrupt new connections which reuse local > > and remote port so the ports stay in use for a few minutes. This is > > standard TCP behavior but only occurs when connections are improperly > > shutdown. Apparently this happens when umounting a tcp NFS mount but > > also for a lot of other tcp based RPC (showmount, rpcinfo). I'm not > > sure who's to blame but it might be the rpc functions inside glibc. > > > > I'd switch to NFS over udp if this is problem. > > Just out of interest. Why does anyone actually _want_ to keep > mount/umounting to the point where they run out of ports? That is going > to kill performance in all sorts of unhealthy ways, not least by > completely screwing over any caching. > > Note also that you _can_ change the range of ports used by the NFS > client itself at least. Just edit /proc/sys/sunrpc/{min,max}_resvport. > On the server side, you can use the 'insecure' option in order to allow > mounts that originate from non-privileged ports (i.e. port > 1024). > If you are using strong authentication (for instance RPCSEC_GSS/krb5) > then that actually makes a lot of sense, since the only reason for the > privileged port requirement was to disallow unprivileged NFS clients. > > Cheers, > Trond > > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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