admins worst nightmare...

[me-5yx05kfkO/aqeI1yJSURBw at public.gmane.org (Matthew Gillen)]

On 03/08/2010 03:43 PM, Stephen Adler wrote:
> Guys,
> 
> I discovered that my 6 terabyte file does not seem to be working 
> properly... I did a copy of a gigabyte sized file to find that the 
> original and copied md5sum's to differ.... uggg.... I'm doing a 
> filesystem check right now, but I'm wondering if you guys have any 
> thoughts on what may be going on with the file system. It's an ext3 file 
> system mapped over a software raid 5 raid array. When I created the file 
> system, I used all the default mkfs parameters for a journaled file 
> system. (i.e. mkfs -J /dev/md127; where md127 is my raid device.)
> 
> When I checked a small file, several megabytes in size, the copy and 
> original had the same md5sum.
> 
> Is there a tool which will give you a summary of how different binary 
> files are? will diff work on a gigabyte sized file?

'cmp' is better for binary files than diff.  'cmp -l' will print out every
difference.  "cmp -l file1 file2 | wc -l" will tell you how many bytes are
different.

Matt