There are 2 routes:
The VNX datasource (which is broken OOTB with 6.4.0, and there is a hotfix for) - this datasource talks to the DART OS NAS head of a VNX, or Celerra + Clariion combo. This route does not require installing naviseccli.exe , because this datasource will run the naviseccli.exe that is installed on the DART head against the back end block array (VNX for Block, or various Clariion).
A Clariion datasource - Install naviseccli.exe - the latest and greatest is fine, but make sure you reduce the certificate validation setting (version 7.32 and higher defaults to a high security certificate validation feature that OCI cannot handle yet). Data source needs ip/fqdn of the clariion/vnx for block, and read only credentials.
A Celerra datasource - will ssh to the DART OS NAS head. Needs the ip/fqdn, and credentials capable of ssh.
Functionally, both are the same. The VNX datasource gives you the ability to have just one instead of 2 datasources, and also allows for discovery of the block portion of the array where the block portion is not IP routable - some "unified" deployments have the block array on an unrouted IP subnet, so undiscoverable by OCI via the traditional Clariion datasource route