yum-deltarpm (Was Thread Hijack - Our package management GUI tools need improvement)

[Mike Kearey]

Horst H. von Brand wrote:
>> I have a local repository with all of Core + some Extras + some Livna +
>> some FreshRPMS in it.
>>
>> If someone had installed everything from my repository when I first
>> created it, and then had do an update to the latest version of
>> everything, they would have to download ~1.5 GB of updates.
>>
>> If that same person had the yum-deltarpm plugin enabled, they would only
>> have to download 638 MB.  That is *including* all the updates that don't
>> have drpms because the savings isn't enough.
> 
> What about people who decide to install OOo and want the latest version
> later on?

Do you mean what happens when user installs Fedora, including the
version of OOo on ISO some time later in the life cycle of the Fedora
release ?

This has made me wonder about the drpm system in general.. The
fedoraproject page has an explanation:

http://fedoraproject.org/wiki/YumDeltaRPM

So, if a user updates a package really late in the life cycle of the
release, and several deltas have been generated over the period, then
there will be some point at which it will be better to pull down the
entire new package and not the deltas. I assume that the deltas will be
cumulative? ie

OOo.0.rpm is in initial release, it is 25MB in size and updates
eventually find their way to the mirror:
- First update OOo.1.rpm = 25MB plus OOo.0-1.drpm = 3MB
- Second update OOo.2.rpm = 25MB plus OOo.1-2.drpm = 10MB
- Third update OOo.3.rpm = 25MB plus OOo.2-3.drpm = 10MB
- Fourth update OOo.4.rpm plus = 25MB OOo.3-4.drpm = 5MB

If someone installs fresh at a time when the mirrors are in such a
state, an update for OOo.1.rpm to OOo.4.rpm will clearly be better to
pull down the full RPM package ( OOo.4.rpm 25M ) and not the cumulative
deltas ( total 28MB ).

Am I correct with my assumptions here ? In the above scenario, loyal
early adopters that regularly update win big time. Slackers and late
adopters don't ;) In general the mirror win big time too as their
bandwidth usage is reduced.


Cheers,
Michael