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To: CIPE <cipe-l,AT,inka,DOT,de>
Subject: Re: Slow file sharing performance
From: Allan Latham <alatham,AT,flexsys-group,DOT,com>
Date: Wed, 3 Sep 2003 09:32:42 +0200
In-reply-to: <3F554433.9070108@rogers.com>
References: <3F515FDA.5080406@rogers.com> <200309021018.24310.alatham@flexsys-group.com> <3F554433.9070108@rogers.com>

Hi James

My own suspicion is still that it is a flow control problem. The file server 
has done some kind of read ahead and is trying to throw data at the client 
much faster than can be pushed down the modem link.

Unfortunately only a careful look at the traffic on all the interfaces will 
help.I think we have exhausted the guesswork!

Best regards

Allan

On Wednesday 03 September 2003 03:30, James Knott wrote:
> I have tried reducing txqueuelen to 3.  First on the NIC in the desktop
> system and then both ends of the VPN.  Neither had any noticable effect
> on the problem.
>
> Allan Latham wrote:
> > Hi James
> >
> > try the effect of reducing the transmit queues on the file server and
> > router. This is not likely to be a satisfactory long term solution but
> > may get you nearer to the source of the problem.
> >
> > Try 100 -> 30 -> 10 -> 3 and note the performance differences. (ifconfig
> > lets you change the queue). You may want to reduce the queue length on
> > the cipe device too.
> >
> > If this makes a significant difference then you will probably need some
> > form of bandwidth control on the file server - we'll look at that if this
> > is in fact the problem.
> >
> > Best regards
> >
> > Allan
> >
> > On Tuesday 02 September 2003 01:21, James Knott wrote:
> >>Allan Latham wrote:
> >>>Hi all
> >>>
> >>>this has generated a lot of replies. It may make it easier if we could
> >>>all see a more precise statement of the problem:
> >>>
> >>>What exactly are you running - hardware, OS and cipe versions at both
> >>>ends? What are the respective performances for both small and large
> >>> files (in each direction)?
> >>
> >>Main desktop system: Athlon XP 1700+
> >>Firewall: 166 MHz Pentium
> >>Notebook:  1.113 GHz PIII
> >>
> >>Red Hat 7.3 on all systems, with CIPE cipe-1.4.5-9 on both ends of the
> >> VPN
> >>
> >>Wben accessing the notebook from the home lan, performance is as may be
> >>expected from a dial up connection for all protocols.  When accessing
> >>the home network from the notebook, everything works fine, except SMB &
> >>NFS.  For example, ftp works OK.  I haven't made any performance
> >>measurements.  However Ethereal shows SMB transfers stop after about 12
> >>packet exchanges.  If I wait an extremely long time, I may see something
> >>show up, but not much.
> >>
> >>>Are directory searches slow or just file transfers?
> >>
> >>Both.
> >>
> >>>If your OS supports pings of various lengths what does this show (in
> >>> each direction)?
> >>
> >>I haven't tried different length pings, however other traffic, such as
> >>telnet, ftp, ssh etc. have no problems.  I have also tried adjusting MTU
> >>on both the VPN and end systems.  Ping times through the firewall are
> >>slightly longer than those without.
> >>
> >>>What are the firewall rules on all machines you have control of
> >>>(notebook, cable modem (if applicable), home router, file server)?
> >>>What NFS sofware are you using - is it TCP or UDP based?
> >>
> >>There are no firewall rules currently running on the notebook.  The VPN
> >>traffic doesn't pass through any firewall rules, though the ethernet
> >>port to the cable modem is filtered and configured to pass the
> >>appropriate UDP ports.  I'm using the NFS that came with Red Hat, which
> >>I believe is UDP.  The firewall rules were posted in another message.
> >>
> >>>One last point not raised so far - what are your transmit queue lengths
> >>>on the file server and the home router. Ifconfig gives you these.
> >>
> >>All are 100.
> >>
> >>>Please excuse me if some of this is already available in the current
> >>>thread but it would be good to get it one place.
> >>>
> >>>I feel that this will go some way to helping everyone on the list get a
> >>>clearer picture - and hopefully an answer.
> >>>
> >>>Best regards
> >>>
> >>>Allan
> >>>
> >>>On Sunday 31 August 2003 04:39, James Knott wrote:
> >>>>I've notice that while my CIPE VPN works, that SMB and NFS access of my
> >>>>home network from my notebook is slow.  However, going the other way,
> >>>>accessing file shares on my notebook, from my home lan is fine.  I'm
> >>>>connecting from my notebook, via dialup ISP and cable modem to my home
> >>>>network.
> >>>>
> >>>>Why is this problem in only one direction?  Is it due to the speed
> >>>>difference between my home network and dial up modem?
> >>>>
> >>>>Any ideas?
> >>>>
> >>>>tnx jk
> >>>
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