[expert] Slow Copy WinXX - Linux/Samba :-(

[Randy Kramer]

David,

Thank you for the information. 

Just so anyone else reading this or the previous emails is not misled, I
should clarify my statement about the 40% throughput on an Ethernet (see
below).  As many people know, Ethernet is a collision sensing, multiple
access protocol.  A station wanting to send data listens on the Ethernet
and waits for a pause to begin sending data.  However, two or more
stations might start sending data at (about) the same time.  When they
sense interference, both stations stop and pause before making another
attempt.  The more stations are on a hub (or common segment), the lower
the throughput (assuming they all have something to transmit -- if some
of the stations don't have anything to transmit, they don't impact the
situation).  (I say this without knowing what "background" traffic may
be going over the Ethernet -- it would not surprise me to learn that
even a station with no (user) "data" to transmit is transmitting various
signals for other purposes (like time synchronization, keep-alive
signals, or whatever).)

BTW: A "switch" (as opposed to a hub, bridge, or coax segment) increases
throughput dramatically because it essentially makes all links point to
point (a maximum of two stations contend at a time). 

Good luck,
Randy Kramer



David Rankin wrote:
> 
> Randy Kramer wrote:
> 
> > I'm sorry I can't be very helpful, but I am curious:
> >
> > David Rankin wrote:
> > > THE PROBLEM:
> > >
> > > Trying to copy an 8 meg file from Win95 to my Linux/Samba box (named
> > > "Nemesis" - for good reason), the transfer speed slows to a crawl. The
> > > Win95 copy dialog box starts out by saying 25 seconds remaining , then
> > > 60 seconds remaining, then 2 minutes, then 5 minutes, and so on.  I HAVE
> > > NEVER HAD THIS PROBLEM IN THE PAST.
> >
> > Are you executing the commands from the Linux box or the Windows box (or
> > does the "from" imply the box you are executing from)?
> > >
> 
> The Windows Box. Using windows explorer I am trying to move a couple of
> directories from the Win95 machine to the new [Applications] share I created
> on the Linux box "Nemesis"
> 
> >
> > > When I set up my server, I copied all of my firm's data from the Win95
> > > machine to "Nemesis" with no problem. Approximately 355 Meg copied in ~
> > > 20 sec. (don't quote me on this, but it was less than a minute - after
> > > not having to reboot the Linux machine since 1/19, my memory fades -
> > > stupid human falability)
> >
> > 355 MB in 20 seconds is very fast -- are you sure that initial copy was
> > successful?  (I'd expect at best, on a 100 mhz Ethernet, closer to 40
> > seconds, and then I'd be impressed.
> 
> I really flew. Everything copied perfectly.
> 
> >  Are the 5 PCs connected to a hub or
> > a switch?
> 
> Cnet 10/100 8 port hub uplinked to a Linksys cable/dsl 4 port router for net
> access. All WinXX clients and "Nemesis" plug into the hub.
> 
> > On larger networks connected by hub, it's common to get 40%
> > or less of the 100 mbps Ethernet as real "thruput".  If the initial copy
> > wasn't successful, maybe that's part of the problem.  (But, if you made
> > the initial copy back on 1/19/01, you would have recognized the problem
> > before now.))
> 
> Thanks Randy
> 
> --
> David Rankin
> Nacogdoches, Texas