Re: [rdiff-backup-users] Rdiff creating a patch file, when there are no changes to the file

[Fran Firman]

You are almost correct.... :)

I did some reading of the rdiff method.

It breaks the old file in to chunks, and creates hashs of the chunks.

Then sends the hashs over to the other server.

Then tries to find data in the other file that matchs the hashs. The
hashs don't have to be in the same place.

Then it will provide a patch file.

So something like this.

Old file = abcdefabc

New file = abcdefabc

ie no changes

the patch file might say thou...

use offset 7, length 3 = offset 1 and offset 7
use offset 3, length 3 = offset 3

Even thou the file hasn't changed.

Go figure.

I found all this out, when I started using the file-statics files, to
tell me what had changed for an ids system, but I kept getting messages
that files had changed, when they hadn't. And it was always the same
files too.

So I am adding in extra stuff to my script that takes the list of
possible changes, and does an md5sum of them to see if the files really
have changed, before alarming about them.

F.


On Fri, 2004-03-26 at 12:44, Martin Pool wrote:
> On 26 Mar 2004, Fran Firman <address@hidden> wrote:
> > I have a file that when I do;
> > 
> > rdiff signature Changes sig
> > 
> > rdiff delta sig Changes patch
> > 
> > I end up with a 14 byte patch file, even thou there are no changes
> > between the file... It is the same file.......
> 
> Try rdiff delta -v 
> 
> The delta probably says, in English:
> 
>   This is an rsync delta
>   Copy the whole original file
> 
> In other words it's a stub diff.
> 
> I would have expected rdiff-backup would check the times first or
> something...