I couldn't get anything at the time. I had discussions with HDS, our Symantec partner and Symantec Support and the best I got was that nothing new is added but the data is changeable. See what the community says or maybe another support ticket.
Another risk on our part but mitigated based on evidence from our environment. We have 3 Stores in a group, 12x2TB drives across the 3, each containing around 55 million files, sharing is enabled across the group. Our backups were not showing any 'significant' increase in volume/file counts, the partitions were closed between 6 months and 3 years. HDS completed the replication for us using an HDS in-house tool and we were satisfied that the data was replicated.
Another gotcha we had was retention categories (we have '0', forever retention set in EV, and the HCP device setting is based on this) and WORM mode. Ensure you set this correctly at partition setup time, we didn't and had a very bad time correcting it (new Streamer partition and replica of the old Streamer partition without device level WORM mode, then some SQL hacks to remove the WORM mode setting on the partition).
Also this type of solution may not be right for you, I'm not recommending anything, just sharing as it worked for us given our circumstances.
