[Samba] Samba vs. Windows

[John Drescher]

On Mon, Apr 12, 2010 at 10:30 AM, Smith, Keenan C.
<Keenan.Smith at jhuapl.edu> wrote:
> All,
>
> We have a fairly vanilla Samba configuration that recently replaced a Windows 2003 server and among other things, serves large (>64 MB) files.  Permissions are all 777.
>
> When running an application attempting to do a single read of these files from a share, we discovered that they were not being served properly.  We also found that copying them to the local drive or changing the ownership of the files to the person running the application seemed to address the problem.
>
> By "properly" I mean that the entire file was not being transferred to the workstations.
>
> We found that there's a 64 MB limit for a single read on 32-bit Windows.  That explained why the enter file wasn't being served.
>
> However, why would changing the ownership of the file or copying it locally make a difference?  Is the 64MB limit only on network services?  Does changing the ownership the file somehow change the properties of the file, making it "readable"?
>
> Also, we found the running the same application from Linux through an NFS mount or from a Windows workstation to a Windows server, the file was served as expected.
>
> It seems like Windows-to-Windows somehow enables buffered reading where Windows-to-Samba does not.  We can't find any obvious Samba settings that would make this work and it doesn't seem to be a Windows issue.
>
> Has anybody seen anything like this or have any ideas for a solution?
>

I have had a problem with large buffered reads and writes under XP. It
turned out to be caused by the following know bug in XP.

http://support.microsoft.com/kb/913872

Not sure if this causing your problem. I solved the problem by
requesting a smaller buffer.

John