[Samba] file differences when copying files to linux, using samba

jeffunit jeff at jeffunit.com
Sun Jan 27 16:46:10 GMT 2008

At 01:03 AM 1/27/2008, Linda W wrote:
>jeffunit wrote:
>>I ran my python program locally on the linux system, and it 
>>reported that roughly
>>100 md5sums for files differed.
>>Any ideas how to track down this problem
>         Could it be a code-page conversion issue?

I am not sure, but I think that involves translating language encoding
from one form to another. I hope that neither samba nor windows explorer
does that silently.

>         Have you tried copying the file over with "cp" from
>windows to your server? (cp from 'cygwin')?

No, but I will try that today.

>         Have you tried comparing some of the differing files and
>looking for a pattern?

Yes. I wrote a modified version of cmp that tries to list all byte differences.
I was looking at an iso image of some linux distribution.
There were three bytes that differed, and if I recall correctly,
they were all one bit differences.

>         Does the "change" get "undone" if you use explorer to
>copy the file back from the linbox to the winbox?

I haven't tried that, but even if it does, I consider it a bug if
a file isn't stored remotely, byte-for-byte the same.

>         I use a similar setup to backup my files -- though I use
>'rsync' from windows to keep the server copy synchronized (which
>gets backed up nightly w/xfsdump.

I have tried rsync several times. I don't trust it, because even when I give it
the --delete option, it has never reliably deleted extraneous files 
at the dest dir.

>         I can't say why, exactly, but I wouldn't trust windows
>"explorer" to copy over such a large number of files.

That is certainly something to consider. My problem isn't that files 
don't get copied
though; my problem is a few bits get flipped in the gigabytes I transfer. That
is scarier to me, as a missing file is much more obvious than a few 
bits flipped.

Both of my machines are as reliable as I can make them, for example both have
ecc memory. If there are setting for samba to do more checksums during transfer
or to use tcp only, I will happily try them out.

Right now I am installing a second os disk, so I can switch os/samba 
quickly, as well as remove the old os disk as a possible problem.


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