Program-related files for this particular install (service executables, etc...)
and databases (where multi nodes will connect to).
Apps and such are stored in the Apps folder configured in the Service Cluster configuration when you originally set up the system. This is a shared path that will be shared across all nodes in a multinode.
If you're interested in scaling out in the future, considering a stand-alone database may be something you want to look into. Sharing the entire Program Files folder available to other nodes is not necessary (or recommended).
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