There's a major bug with fedup to Fedora 21 right at the moment, discovered this morning by Robin Lee (thanks Robin). We should be able to deal with it some way or another in time for Beta release day, but for right now it's not a very good idea *at all* to try and upgrade any system you care about to F21 with fedup. (Of course, it's never a good idea to upgrade to a pre-release without a recovery plan!)
https://www.happyassassin.net/2014/10/31/psa-dont-fedup-to-fedora-21-right-n... https://bugzilla.redhat.com/show_bug.cgi?id=1159292
Of course, if you want to help out with solving this, it'll be a great help. It'd be good to have folks confirm that the bug happens any time the 'install updated packages' boot takes more than 15 minutes, and maybe that the scratch builds I've posted in the bug - https://bugzilla.redhat.com/show_bug.cgi?id=1159292#c18 - solve it (the final fix may be different, but that bodge should at least illustrate that the problem is really what we think it is, if it works).
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