One minor change to ease the situation would be to not push everything out to the mirrors at the same time, but to do it in smaller chunks. For example, once the rpm's are pushed to CR, those packages (and the unchanged packages from a prior release) could be pushed to the new os directory. Perhaps along with a note saying that the packages are here only for seeding the mirror network for the eventual release and should not be used yet. Repodata wouldn't need to be included at this stage. The centosplus, extras etc. directories could be populated at this stage as well. Syncing those out would take a few days. During syncing, the devs + QA team would be busy spinning and testing the .isos. Once they're deemed OK, they could be pushed to the master for syncing to mirrors, along with the few missing packages and repodata for the os directory. The amount of data transferred would be the same as before. The advantage of this approach is that there would be less demand for bandwidth at the .iso sync stage, because the other bits were already synced to most of the mirrors some days ago.