I have finished the cluster upgrade in my lab cluster and it has been a great experience.
smarconsole looks after pretty much everything and it provides good information in real time about what is going on.
These are the steps I followed:
1) I pre downloaded the r81.20 image in both cluster's gateways
2) install on non active member only, untick the failover option
3) manual failover: clusterXL_admin down; clusterXL_admin up; cphaprob stat
4) install on non active member only, untick the failover option
5) deactivate mvc: cphaconf mvc off
6) install the policy (not really required as smartconsole did it automatically, but good to see that policy install accelaration works and the policy got installed in no time)
Summary:
I think smartconsole gradual upgrades is a great feature, but I would like to see a couple of improvements in the future releases:
1) Better firmware download management - in sync with cpuse
2) Automatic MVC deactivation at the end of the process
3) More verbose mode to present all the cpuse process status information in real time in smartconsole