Yum deltarpm

[Warren Togami]

Dennis Gilmore wrote:
> On Saturday 13 January 2007 12:40 pm, Ahmed Kamal wrote:
>> FYI, this yum deltarpm support, is based on that same deltarpm package that
>> is made by suse. This suse package can create new rpms from drpm + (either
>> ondisk files, or old rpm). Either way, a new rpm is created, then
>> installed. Never does it replace files directly. Not sure why this would be
>> bad security wise
> 
> I personally don't like the idea of binary delta's  there are too many 
> variables  with them and too much overhead.    for instance say we update 
> cups 4 times during the  life of a release.  that means we need to create 4 
> delta's  as the end user can have 4 possible states of the package. 

Then limit the delta to the most common update paths.  If the desired 
delta doesn't exist when the user tries, it can fall back to download 
the full RPM.  No big loss.

> most packages are so small that i don't think the overhead is worth the pain. 
> OOo and a couple of others i could see maybe,  but otherwise I personally 
> don't think its a good idea.  It means mirrors need to carry more data. 

Then provide deltas only for the biggest things that would benefit the 
most from delta patching.  All else download the original RPM.

Some algorithm could attempt to make deltas, and offer deltas where the 
download savings are something like > 80% and > 2MB.

Warren Togami
wtogami at redhat.com