[lug] Samba, VPN, unison & speed

[John Hernandez]

Ben, with 90ms RTT latency, even a modest TCP window size of 56 kbytes
should suffice to "fill" a 5 Mb/s pipe, so maybe it's something else.

My advice would be to try a bulk TCP transfer using a straightforward
protocol like HTTP, between the same two hosts over the same VPN.  If this
achieves substantially better throughput, continue digging into SMB issues.

If HTTP transfer also seems slower than you'd expect, fire up Wireshark and
capture a chunk of the flow.  When viewing your pcap, turn of unhelpful
protocol analysis like NETBIOS and SMB.  Interesting things to look for
would be signs of frequent packet loss (indicated by retransmissions),
window sizes and use of window scaling (in the initial handshake options).
 The TCPTrace graphs can also tell you a lot.  (Try zooming in).  There's a
wealth of information within.

On Wed, Jan 4, 2012 at 2:18 PM, Ben Luey <bluey at iguanaworks.net> wrote:

>
> > sorry i don't have an answer for you.  but i was curious as to what
> method and or commands you use to determine those 20% and 50% "best"
> bandwidth utilization figures.  i would like to be able to determine
> similar types of things if you care to share.
> The glib answer is math :)  On Windows, I use process manager to look at
> the traffic on the line and it reports in Network Utilization. So if I'm
> on a 100 Mbps  ethernet connection, but I have a 1.5Mbps internet
> connection, my max through-put  is 1.5%. So 0.5% utilization is 33% of
> my theoretical max. Under Linux I use gnome's system monitor (process
> monitor? I can't remember) and it reports in kB/s, so I multiply by 8 to
> get it until kbps and take the ratio compared to what I should get based
> on my network connection to the machine.
>
> In response to John, I get ~90ms on pings. Samba is running 3.5.6 on a
> LAN with a mix of XP and Win 7 machines. Can samba use smb2 on a mixed
> network, or if there is one old machine, does everything have to be on
> smb1?
>
> Ben
>
>
> >> I'm running Debian Squeeze with Samba 3.5.6 and OpenVPN. It works fine,
> >> but using file sharing over the VPN is very slow. I've read that the smb
> >> protocol doesn't play nice with network latency, etc, so maybe there is
> >> nothing I can do about it, but I'm curious if anyone has any
> >> suggestions. Transferring large files utilizes at best 20% of bandwidth
> >> (direct wireless connetion to the vpn, or fast internet connection) (On
> >> wired 100MB/s ethernet without VPN, I get 50% utilization). Doing lots
> >> of dirs and small file look-ups are significantly slower. This is
> >> particularly a problem when using unison to sync diectories on a Windows
> >> machine (fastcheck is enabled in unison), which is really mostly what I
> >> care about.
> >>
> >> I've tried adding
> >> max protocol = SMB2 to samba, but speed tests under Win 7&  Ubuntu 11.10
> >> were the same. Maybe the solution is not to have unison run on top of
> >> windows file sharing, but users don't have shell/ssh access so I don't
> >> know how else to do it.
> >>
> >> Any ideas appreciated. Thanks,
> >>
> >> Ben
> >> _______________________________________________
> >> Web Page:  http://lug.boulder.co.us
> >> Mailing List: http://lists.lug.boulder.co.us/mailman/listinfo/lug
> >> Join us on IRC: irc.hackingsociety.org port=6667
> channel=#hackingsociety
> >>
> > _______________________________________________
> > Web Page:  http://lug.boulder.co.us
> > Mailing List: http://lists.lug.boulder.co.us/mailman/listinfo/lug
> > Join us on IRC: irc.hackingsociety.org port=6667 channel=#hackingsociety
> >
>
> _______________________________________________
> Web Page:  http://lug.boulder.co.us
> Mailing List: http://lists.lug.boulder.co.us/mailman/listinfo/lug
> Join us on IRC: irc.hackingsociety.org port=6667 channel=#hackingsociety
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.lug.boulder.co.us/pipermail/lug/attachments/20120104/3f01a6b8/attachment.html>