We need to install SQL SP2 and CU1 at multiple sites on SQL/WIN 2008r2 EE clusters with 5 nodes, 22 sql instances, and thousands of databases. The problem is that MS has deployed a non-scalable installer; it runs a Remote Discovery process (RunDiscoveryAction) once for enumeration before installation starts, then again for EVERY sql instance. Each Remote Discovery takes 2.5 minutes, which may not sound too bad until you do the math:
((DiscoveryTime * number of Hosts) * (number of intance +1) ) * Number of Patches = Discovery Time
Our Math is ((2.5*5)*(22+1))*2 = 575 minutes of discovery time.
We've tested this in our lab (Win/SQL 2008r2 EE 4-node cluster with 20 instances) and found the math is correct.
There has to be tons of other shops that have run into this issue. Anyone out there have a solution?