I've never had a problem with the backup not having enough space, and as a matter of fact, it backed up fine yesterday before I did the iOS 8 update. I also upgraded my iCloud storage to 20GB last week when they changed the plans. So now, by iCloud says I am using 10.1GB for my iPhone, 1.2GB for my iPad, and that there is 8.7GB free. If I have 20GB, why can't it back up my iPhone? Does iCloud really need TWICE the space (enough for two full backups) in order to backup? Shouldn't it backup and then delete the old backup? Last week, I had 15GB total iCloud and it's always backed up fine. Ideas?