[Samba] Copying Files from XP to Samba (help needed)

[Daniel Lindgren]

I am also having performance problems writing to a Samba share (see previous
post about tcpdump) and I have seen a strange phenomenon: if I start tcpdump
on the Samba machine, performance increases 20 times. It would be
interesting to know if you also experience the same, just start tcpdump and
redirect output to /dev/null while/before copying files.

Regards,
Daniel Lindgren

2006/10/9, Peter Daum <gator_ml at yahoo.de>:
>
> I am still desperately trying to figure out why I get such a horrible
> performance trying to copy files from XP to Samba (below is my
> original post to illustrate the context. Meanwhile, I found a
> pretty remarkable pattern in the network traces.
>
> Generally, the packets send from the XP machine look like this:
>
> 01: WriteAndXRequest 60 kBytes (1392 bytes payload)
> 02: 1460 bytes
>     ...        (usual time delta between 2 packets < 0.0001 secs)
> 42: 1460 bytes
>     < < < < delta: 0.05 - 0.3 secs > > > >
> 43: last 188 bytes
> .. WriteAndXResponse from Samba machine, da capo
>
> It seems like what is slowing the transfer down so dramatically, is
> the long gap before the last 188 bytes are sent. I can't see anything
> reasonable the XP machine could be waiting for - it already got the
> ack for the last preceding packet.
>
> To emphasize again, this is not a general networking problem between
> the 2 machines; it only (at leas AFAIK) occurs  when copying large
> files from Windows XP to Samba shares (and at that occasion I could
> reproduce it with all the Samba servers and XP clients that I checked
> so far)
>
> Any help would be greatly appreciated.
>
> Regards,
>                              Peter Daum
>
> > I noted an extremely poor performance when copying big files from
> > a windows xp client to a samba share. The exact version of samba
> > does not seem to matter: I tried several different samba servers
> > with versions between 3.014 and 3.0.23b running on Linux 2.4.32
> > and 2.6.17 (machines and network otherwise idle, clients connected
> > via fast ethernet, servers via Gbit; network performance in both
> > directions around 95 Mbit/s). I made several tests copying a 1GB
> > file with Windows 98 and Windows XP clients. Reading the file from
> > the server takes predictably around 105 seconds (~9.75 MB/s).
> >
> > Writing to the server takes only slightly longer on Win98 (130
> > seconds, ~8 MB/s) while the same takes approximately 45 minutes
> > from a XP client (I don't know whether this matters, I noted that
> > on the XP write test, the directory listing on the server
> > immediately shows a file with the final size - obviously a sparse
> > file, repeatedly invoking du shows the gradually increasing actual
> > size).
> >
> > I wrote a little test program that just writes data to a file and
> > shows the throughput; the transfer rates I get that way are pretty
> > reasonable, so it is not a general problem but something that only
> > occurs on specific operations like copying.
> >
> > Tracing the network traffic also didn't tell me what the problem
> > might be: XP uses for copying as well as for other write
> > operations WriteAndXRequest, the only peculiarity I noticed is the
> > slightly exotic block size of 61440 bytes per request when copying
> > (which also doesn't seem to be the problem - Win98 uses the same
> > block size with WriteRaw)
> >
> > Has anybody else made similar experiences? (Since I could see this
> > issue with differently configured servers/clients, it should not
> > be just my personal problem. Of course in most settings where the
> > data usually goes mostly from the server to the client it is not
> > obvious)
> >
> > Any ideas what's going on and what to do about it?
> >
>
> --
> To unsubscribe from this list go to the following URL and read the
> instructions:  https://lists.samba.org/mailman/listinfo/samba
>