Silly reads from WinXP/OfficeXP against Samba 3.0

[Oktay Akbal]

This does indeed work around the problem. At least what when we talk about
performance on editing the file. But I still think, that a bit to much
network traffic is caused (not that high as before).

At least with samba3.0 and one specific Test-Document, setting CacheSize
to 2048 or higher works. 512 or 1024 not. THis might be because the
Test Doc is about 2.5Mb.

And of course this has not been seen against WinNt4- or W2k-Servers.
I read about "rabbit-pellet", but I assume that noone has further hints
on how this is caused on non-Win-Servers ?

Oktay

> Hi,
> 	While it's not quite the same as your environment, we saw very
> similar behaviour, so maybe this will help.
>
> We had:
> Windows 2000,
> Word 2000, with "track changes" on.
> Rational Reqpro (forget version). - which integrates word documents with
> an SQL DB for project requirements management.
>
> Particularly when scrolling through the document, word would go insane
> with <512 byte reads - as far as I can tell, the track changes mode
> means the word document has it's content split all over the file, so
> word has to keep jumping around all over the place. This is made worse
> by the fact that by default, word only buffers about 64K of the file in
> memory, and scrolling meant we "jumped out" of that buffer constantly.
>
> On a windows<->system, this behaviour is hidden by oplock caching.
> However, word had a habit of opening the document 2 or 3 times, which
> causes samba to break the oplock. I assume windows has some magic to
> detect this behaviour, and keep the client cache valid.
>
> We worked around the problem with a registry hack to cause word to
> buffer more of the document at a time:
>
> [HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Word\Options]
> "CacheSize"="512"
>
> There's probably a similar option for XP.
>
> Cheers,
> 	T.
>
> > -----Original Message-----
> > From: Volker Lendecke [mailto:Volker.Lendecke at SerNet.DE]
> > Sent: Wednesday, July 16, 2003 12:28 AM
> > To: samba-technical at samba.org
> > Subject: Silly reads from WinXP/OfficeXP against Samba 3.0
> >
> >
> > Hi!
> >
> > Here I have a repeatable case: Office XP SP2 on WinXP reads a
> > file, and
> > during the first requests everything looks fine. Then after some time
> > the machine starts to read *HUGE* amounts of 512
> > byte-fragments from the
> > .doc-file. This results in ~140000 packets whereas the same operations
> > only use ~4000 packets when the file is on 2k.
> >
> > I already tried 'max xmit = 4356' to match 2k buffer size negotiation,
> > but that did not help. One thing that I also found is that the client
> > seems to actively use the multi-request feature of 2k.
> >
> > I can provide sniffs and tests with a patched Samba, but I'm
> > currently a
> > bit lost. Staring at a dump of 140000 packets is not exacly easy :-(
> >
> > Any idea anybody?
> >
> > Volker
> >
>
>

Oktay Akbal
S-Tec Datenverarbeitung GmbH
Feuerbachstr. 8
68163 Mannheim
Tel: 0621-4185070
Fax: 0621-4185071