In order to try and cut down on the amount of space on the mirrors, it might be reasonable to consider splitting the archive module. Some of that stuff is only of historical interest at this point, and there might not even be any point in having it mirrored at all. (Given that we really don't want people actually using it.)

I know that the older releases really aren't large compared with the modern ones, but if we kept, say, only the last ten(?) releases in archive and moved everything older off to either a "historical" rsync module or just a separate server somewhere that isn't rsyncable, we'd save something on the order of a terabyte, or nearly 10% of a full mirror load. Of course, there's pretty much no churn of that content so there's no bandwidth savings.