Just an additional thought: You can of course mirror vol0 (your 'root + data' volume) from Filer A to vol1 on Filer B as Stephen states.
Right, but the issue was my in-ability to pay attention to the "PreReq's" on 530 of the SAG.
1) License - Ok, had that. 2) Off-line volume for mirror - Didn't quite understand it at first, but do now. This lead to reformatting BOTH filers. I tried to "Cheat" but got caught 3 bullets down. 3) Source on-line - Ok,had that. 4) Source not mirror - Ok, had that. 5) Mirror>=Source - I didn't have that when I was trying to cheat. 6) Mirror <> Root - I completely glossed over it, but would have solved other issues I had (And answered the issue.)
Tuc/TTSG