Which drives are mirrored in raid10 array?

# for d in sd{a..d}; do echo -n "$d = "; dd if=/dev/$d skip=200 bs=1M count=1 2>/dev/null | md5sum | tr '\n' ' '; sdparm --page=sn --quiet /dev/$d | grep -v "page:"; done

Play with the skip option if results don't split into pairs.