DeltaISOs

[Andre Robatino]

Should also mention that since the difference between zsync and deltaisos is
either downloading changed RPMs in full vs. using deltarpms on them, this means
that if both were provided, then people with either sufficiently fast
connections (meaning around 5 Mbits/s) or a very slow PC would be better off
using zsync (since downloading a full RPM is faster for them than downloading
the deltarpm and applying it), while others would be better off with deltaisos.
In fact, it should be exactly the same people who find that updates are faster
with yum-presto disabled (download full RPMs) vs. enabled (download deltarpms
and then apply them).

Since yum-presto is currently enabled by default, I think deltaisos should be
provided just for consistency. Having high bandwidth has nothing to do with
being a good tester, so there's no reason why testers should be expected to have
more bandwidth than ordinary users.