Suppose I create a storage A, and then a second storage B with the -copy
flag.
Do I now have to backup to A, and copy to B, or can I instead backup to B and copy to A?
Probably not a common use case, but out of curiosity, can I sometimes backup to one, and sometimes to the other, and occasionally run copies in either direction? (Perhaps I have a storage device at home, and one at work, and want to backup a laptop to whichever is local.)