on the 2nd ZD3000 controller, you just need to buy this -->
803-3000-1RDY - part no
WatchDog ZD3000 series
Redundant Controller Support, 1 Year. Includes Support & license upgrades
to bring redundant ZD to the same level as the primary ZD. Must purchase with
a ZD3025 (PN # 901-3025-XX00) or use with existing redundant ZD3000
this gives you support + necessary licenses for 1 year.
for more info - talk to your ruckus sales rep