samba - Sep 1998 - Samba AutoCAD 14 problem - info (maybe a solution....)

"Kelly Uehling" <kellyu@mwcad.com> writes in comp.protocols.smb:
>This has been an ongoing problem with Unix SMB file servers. While perusing
>the autodesk.autocad.network newsgroup, I came across someone else having
>the same problem with a Syntax 5.3 server. Syntax's response was as
follows:
>
>    By Syntax Technical Support (Support) on Thursday, September 3, 1998 -
>03:53 pm:
>
>    The problem:
>    When using AutoCad 14 on an NT workstation w/Service Pack 3, accessing a
>file from a TAS NB realm volume, the file will be opened read-only
>occasionally.
>
>    Background:
>    When we investigated this problem using an NT workstation without SP3
>the problem was fixed by reducing the mux value to 1. When we did this the
>NT did not try to do named pipe opens for srvsvc or SMBtrans API's. Now
with
>SP3 the NT will do these calls even with mux set to 1.
>
>    The problem has been narrowed to the SMBtrans API call comming between
>two SMB's, SMBgetattr filename.dwk and the SMBopenX filename.dwg. The
.dwk
>file does not exist and this should not cause a problem. It is interesting
>to note that the r/w open of the .dwg file never fails and even where
>AutoCad is saying the file is read-only the file is being opened
>successfully r/w.
>
>    It is also interesting that AutoCad is quite flexible in the way it does
>things. No two traces are exactly the same even though the same actions are
>done each time. The traces are basically the same but actions can come in
>different orders which seems to point to multi-threading of the application.
>
>    It is also interesting that AutoCad is quite flexible in the way it does
>things. No two traces are exactly the same even though the same actions are
>done each time. The traces are basically the same but actions can come in
>different orders which seems to point to multi-threading of the application.
>
>    It is suspected that the API transaction is somehow causing AutoCad to
>pick up the failure of the getattr SMB for filename.dwk as a failure for
>filename.dwg.
>
>    AutoDesk has an ackowleged problem with NT using a Novell 32 bit client
>that is exactly like this. Although this is a different realm it may be the
>same problem to the application.
>
>Maybe this will help track the problem down in Samba. Maybe it won't.
Kelly - you're a *wonderful* person !

This looks *exactly* like the issue I see in the Samba
logs - the getattr failure for <filename>.dwk.

The problem is that if you set maxmux to 1 in
Samba then NT stops being able to load user
profiles from a Samba share (that's why we upped it 
to 50, as NT uses). If you're not hung for one problem 
you're hung for another.... :-).

So what it *actually* looks like is a bug
in the Microsoft redirector that is compounded
by the way AutoCAD 14 checks for read only.

The way to check this is for Samba users having
this problem to set in the [global] section of
their smb.conf the parameter :

max mux = 1

and re-start Samba. If this information is
correct the AutoCAD problem will not then
occur (although you will not be able to
store NT user profiles on that Samba server
due to the *other* bug in the NT redirector :-).

My guess is that this doesn't happen on NT
as theirs is a multi-threaded implementation
and just happens to process the SMB requests
that AutoCAD sends in a different order - if
they processed them fist-come-first served, as
Samba does then they'd get the same problem with
AutoCAD !

Well I never thought I'd say so, but if this
fix works then "Thanks a *BUNCH*, Syntax :-)".

Cheers,

        Jeremy Allison,
        Samba Team.

-- 
--------------------------------------------------------
Buying an operating system without source is like buying
a self-assembly Space Shuttle with no instructions.
--------------------------------------------------------

>The way to check this is for Samba users having
>this problem to set in the [global] section of
>their smb.conf the parameter :
>
>max mux = 1
>
>and re-start Samba. If this information is
>correct the AutoCAD problem will not then
>occur (although you will not be able to
>store NT user profiles on that Samba server
>due to the *other* bug in the NT redirector :-).

Could they have the best of both woulds, mabye a share level option that did
some re-ordering

[autocad]
    fix autocad = yes

Just a thought

-Eric