Thomas Hille wrote:
Am Montag, den 14.03.2005, 08:18 +0100 schrieb Florian La Roche:
On Mon, Mar 14, 2005 at 01:59:07AM +0000, Joe Desbonnet wrote:
I've done tests some time ago that showed a 4.8 factor to reduce bandwidthI have more results from my experiments in RPM delta compression. I've posted the results so far here: http://www.wombat.ie/software/rpmdc/index.shtml
Conclusion so far: assuming someone has the distribution RPMs
available then an entire
update repository (about 1GB) can be generated from 200MB of files.
I hope to post my code once I clean it up a bit (it's implemented in Java currently).
Must check out rdiff also...
needs for RHEL update releases. Big drawback will be the need of the previous
packages, so this might again be only something for a local server to
download updates, but not for normal client machines.
Still the savings look very nice, so I think we should continue looking at
this.
Just to give my 2 cents....
The drawback you talk about could be eliminated, when you diff not the
whole rpm, but instead for the single files in it. - These are present
on the client machine. Then the only problem that arises are corrupted
files. So you would need to check the md5 before.
Yep. All this has been known since 1998, see rpm-list@xxxxxxxxxx archives..
Josh McDonald, the xdelta guy, even had a proof-of-concept implementation in (iirc) xdelta-0.18 for *.rpm packages.
Ooops, Red Hat chose not to maintain <rpm-list@xxxxxxxxxx> archives, too bad.
Maybe doing the diff on the single files also could help compress the rpms, that were not compressible using the whole rpm (omni-foomatic etc.)
Nevertheless, the recent OOo update makes me believe, that we should
really think about anything that reduces bandwidth (even in the time of
common broadband access).
I ask:
If you have to rip apart a *.rpm package into it's components in order to achieve
the goal of minimal bandwidth used to transfer a package, then what exactly is
the point of putting the contents in a *.rpm package in the first place?
73 de Jeff
