yum-presto - fast updates for Fedora 7

[John Wendel]

Rahul Sundaram wrote:
> RavenOak wrote:
>> What about server-side?  Either the server or the client needs to do a
>> binary/rpm diff.  
> 
> It's on the client. Most of our mirrors prefer not running any code on 
> the server.
> 
> If it's the client, that really doesn't cut down on
>> bandwidth because the client would have to d/l the new package to diff
>> it against the old one (and if it didn't have the old one, d/l it
>> too).  
> 
> It doesn't need to download the old one too. See 
> http://fedoraproject.org/wiki/YumDeltaRPM
> 
> Rahul
> 

"It's on the client", doesn't appear to be correct!

The diff-rpm must be generated on a server (somewhere) and pushed to 
the mirrors along with the full-rpm. The mirror servers don't run any 
special code, they just host the full-rpms and the diff-rpms.

The client gets the diff-rpm and constructs the full-rpm using the 
diff-rpm and the previous full-rpm (which has to be saved on the client).

Regards,

John