Bug with binary file backup.
Thu, 7 Feb 2002 14:05:45 -0500 (EST)
Thanks for the advice.
4. This was a nogo. rdiff's output (from the diff of the 2 tarballs) was
~650Megs. Each of the distro's was approximately the same size. I assume
that this was because of file offsets within the tar file and because
lots of binary info was present. The algorithm just didnt work for this
3. I tried rsync 2.5.2. I downloaded this last night. Although It
presents a pretty interface, It is still broken. The delta files
generated were about the same size as the directories you create (~120Megs
- 150Megs) but failed to apply cleanly in many different cases with
1. With rdiff-backup I had no problem with the exception of files with
identical times, sizes, names, etc. This problem was worked around by
adding a touch to my scripts. I will be using this system. I plan on
rpming it for our needs and writing some utility scripts.
Let me know if you want any testing, benchmarking numbers, rpms etc.
Question - Why is python 2.2 required? I haven't tried it with Python
2.1, but It would make my life easier if i could just rely on the Python
2.1 rpm. What new functionality do you use?
On Wed, 6 Feb 2002, Ben Escoto wrote:
> >>>>> "DS" == Dan Sturtevant <email@example.com>
> >>>>> wrote the following on Wed, 6 Feb 2002 18:33:26 -0500 (EST)
> DS> What I was doing was maintaining a tree of the original
> DS> distribution (Plogic-7.1-5) that I was working with and then
> DS> creating deltas by running #rdiff-backup Plogic-7.1-6/ backup/
> DS> followed by #rdiff-backup Plogic-7.1-5 backup/
> DS> I had hoped that this would create a directory structure that
> DS> the end user could place into a copy of the original
> DS> Plogic-7.1-5 tree to get it up to Plogic-7.1-6.
> DS> This creates the opposite problem: I want older timestamps from
> DS> Plogic-7.1-5 to be pushed on top of Plogic-7.1-6 to generate the
> DS> rdiff-backup-data directory. It will almost always be the case
> DS> that older files should replace newer ones in my case.
> Ok, I can think of 4 things that you could try:
> 1. Use my program. The problem you ran into was that files seemed
> identical because:
> DS> My test directories had the same time because they were coppied
> DS> over to my local machine at the same time.
> So, it seems if you waited a second (e.g. cp ...; sleep 1; cp
> ....) your immediate problem would go away.
> 2. Instead of using CVS use something like PRCS (?) which is better
> at taking binary differences.
> 3. I seem to remember someone contributing an extension to rsync
> called rsync+. I don't know if it has been adopted yet, or how
> stable it is, but the idea is to save the information between
> rsync sessions. For instance, suppose server 1 always changes,
> and servers 2 and 3 are supposed to be identical copies of 1. I
> think rsync+ could be run on 1 and 2, and then would produce a
> file that could be transmitted to 3, so 3 could be updated without
> rereading all the files on 1 again.
> 4. Make a big tar (uncompressed; just tar) file like Plogic-7.1-5.tar
> or Plogic-7.1-6.tar and then run rdiff on those two files. You
> can compress the diff and send it around.
> I don't know your situation very well, but I would try (4) first, then
> (3) if it is stable and easy to use, then (1) and then (2).
> DS> You seem to have a great deal of experience in this domain.
> Yep, on the internet no one knows that you're a dog. :-)
> Ben Escoto