I would not put the OS on the SAN. Where would the OS Cache be configured. This is usually not done, what are the benefits of putting the OS on SAN? It is an interesting thoughts and if you do tryout do share the results.
Also I understand sometimes
true cost of DAS is also more considering Hadoop replication , but this is how
Hadoop is thriving (One of the key tenets of Hadoop is to bring the compute to
the storage instead of the storage to the compute.)