oops, i thought we were talking about initiator cascaded groups. It does not have to be cluster allocation. For example i have an Oracle system where i have data file systems and archive log file systems. I would like to use FAST for my data file systems so then can go up and down between my T1 and T2 tiers but keep my log file systems on the same teir (because of its sequential workload not very beneficial to be on EFD tier). So before code 76 i would have to create two different storage roups, two different masking views,  one would be for my oracle data TDEVs and another would be for my log TDEVs. Now i can have just one masking view, one cascaded storage group.
Does any body help me with the practical use of Cascaded Storage Groups in Vmax allocation.?   thanks in advacne  Raj
Practical use of Cascaded SG