F21 downloads repository metadata in 3 places!

[Chris Murphy]

Fresh installation of Fedora 21 Workstation, accepting defaults, I
then reboot and notice the following contents of /var/cache, filtering
out things not relevant for this discussion (which also happen to not
change between the three states).

Starting point right after installation:

[root at localhost cache]# du -sh *
16K dnf
85M PackageKit
4.0K yum


Login, wait for ~ 1/2 hour:

[root at localhost cache]# du -sh *
94M dnf
446M PackageKit
4.0K yum

That's 455MB of silently downloaded data, by default. Upon doing a yum
upgrade, but rejecting the actual upgrade:

[root at localhost cache]# du -sh *
94M dnf
446M PackageKit
137M yum

Ummm, that's a metric shit ton of data to download for a brand new OS.
No doubt this is bigger by now for Fedora 20 since most every package
will have been touched by an update, and likely is well over 1GB to
silently download.

I suggest the following short term change:

1. dnf should not be downloading its metadata in the blind by default;
yum doesn't, why is dnf doing this? And there's the hourly refresh it
does by default also. I like this behavior for me, but I think it's
simply an inappropriate default considering various bandwidth
limitations that still exist in the world.

2. PackageKit very aggressively starts downloading both metadata and
updated packages upon first login. I think this should be delayed so
the user has an opportunity to disable it; and then Software or
Settings needs a UI so that it can be disabled. The UI could
differentiate between automatic checks for updates (metadata) vs
automatic package downloads; or even between application vs OS
downloads.

But backing this up, the OS needs to ask for permission before
additionally downloading 50% to 100+% of the install media size. I
don't really care if this permission is conveyed in the installer UI;
or g-i-s or a notification; but the current behavior is really
presumptuous.


-- 
Chris Murphy