Request for Comments: updating RPMs using binary deltas

[seth vidal]

On Thu, 2004-01-08 at 20:17, Lamar Owen wrote:
> On Thursday 08 January 2004 01:54 pm, Jef Spaleta wrote:
> > Is providing a low bandwidth solution to updates really worth the extra
> > testing and the extra mirroring..the extra drain on development and
> > building resources. Are we saying that low bandwidth people are going to
> > have to choose between rpmdiff packages and being able to use custom
> > packages or Fedora Alternatives or 3rd party alternative rpms safely and
> > effectively?
> 
> When updates exceed 100MB _ALL_ users are low bandwidth, and dialup users are 
> locked completely out.  So they don't update at all, get hacked, and blame 
> Linux.


I'm going to be a bit of a snob and say the following:

When the updates exceed 100MB I'm _still_ not a low bandwidth user.

If you want to spend this time more effectively do the following. write
the code to take librsync and rpmlib so you can sync up two dirs of rpms
with entirely different file names to one, current set.

so if you have foo-1.1-1.i386.rpm on one end and foo-1.2-1.i386.rpm on
the other end - an rpm-aware rsync would be able to know that foo is one
package and those files should be diff'd against each other to take the
bits from  foo-1.1-1.i386.rpm to make foo-1.2-1.i386.rpm

This would help mirror operators quite a bit. Thereby increasing the
number of mirrors and hopefully helping out the low bandwidth users by
there being more mirrors.



> > that argument. If official mirror maintainers see potential problems
> > with carrying the rpmdiffs...their expert opinions need to be taking
> > with grave attention.
> 
> Absolutely.  I would think mirror operators would love to reduce the load on 
> their servers, which this would as I've envisioned it.  And their bandwidth 
> bill might even go down.

A fair number of the mirror operators don't get bandwidth bills. A lot
are at universities. And the mirror operators I've run into wouldn't
like a system of hundreds upon hundreds of patches let's say 2 for every
potential released errata for any package. It would eat up more time on
rsync and in general be a pain to deal with.

-sv