Did you or anybody else run across anything about WannaCry being able or unable to get to a mounted volume other than the one it's infected?
No.
The prevailing wisdom is to backup remotely (where remote seems to mean off-site) for protective/restorative purposes.
It may take a while before it or similar malware jumps into the Apple realm, but it would be good to know if a separate volume (even though physically attached to the same computer) is sufficiently "remote backup" to escape the ravages of ransomware.
