[Samba] Copying (Samba -> WinXP SP2) MATLAB generated .jpg files very slow.

[Jeremy Allison]

On Tue, Mar 11, 2008 at 12:08:36PM -0400, Paul Griffith wrote:
>
> Greetings,
>
> This is a interesting problem. One of our researchers uses MATLAB to 
> generate jpg files as part of his vision research. When he copies these 
> files from the file server, it is very slow. I tried 3.0.28a and I see the 
> same problem as we have with 3.0.28.
>
> Here are some interesting stats.
>
> 1) MATLAB generated files:
> command: robocopy Y:\23_1 C:\23_1 /e
> dirs: 2
> files: 262
> bytes: 12.75MB
> time: 3min 15 seconds
>
>
> 2) Same files resaved with IfranView
> command: robocopy Y:\23_1b C:\23_1b /e
> dirs: 2
> files: 260
> bytes: 22.05MB
> time: 19 seconds
>
> This is only a subset of the files that the user copies. The full directory 
> consists of 8939 files over 101 directories for a total of 402MB and this 
> takes 1 Hr,12 minutes and 5 seconds (Samba 3.0.28 -> WinXP SP2) verses 3 
> minutes 30 seconds for a WinXP SP2 -> WinXP SP2 copy.
>
> When I write the files back to the same Samba server the results are about 
> the same for the MATLAB and IfranView jpg files.
>
> Any suggestions, since this only happens with MATLAB generated files?

Does MATLAB add any stream metadata to the files ?

robocopy may be doing something dumb with files with
associated streams.

Jeremy.