My organization has implemented the HDI/HCP solution and it is not performing as billed. Namely, when the data was injested the number of copies that it makes was not controllable. In one instance, with a particular supported agency, it has grown exponentially to 130tb. Hitachi told us it would hold a certain number of copies under "Historical" but instead it does not stop holding copies. Hitachi is saying they have a developer working on a fix to reduce the copies but with no financial incentive to do so I see little hope of this happening.
We have now decided on trying another course. Namely, we are implementing Commvault and would like to stop this agency from using the HDI/HCP as its file share solution (we would give them a traditional server 2012 file share solution) and archive this 130tb out with a Commvault front on it for doing searches (if they even happen!).