Legal (contract) requirements
In our case, the data we store almost always belongs to our clients. The contracts we agree to with our clients almost always force us to be responsible and accountable for the security of the data while it is in our hands. So there's no question really - cloud storage is impossible because then we would be accountable for security breaches that a cloud provider would have.
But aside from that, there are plenty of software products we use that can only store and access files on a mapped drive-letter or UNC path. Cloud products, and even SharePoint won't work.
To combat the problem of unnecessary file storage, get a product that moves the least-recently-used files to a secondary storage array, replacing the file with a shortcut or a stub. Arkivio or Rainfinity can automatically migrate files that haven't been accessed in say, 6 months to "near-line" storage. So the important files can be close to the user in each of your offices. The rarely-used ones can be far away at your main datacentre, and there will just be a brief delay when opening them. The secondary storage array doesn't require frequent backups. Maybe none, if older data is not deemed crucial in your company. (e.g. old sales quote files are usually not keepers.)
So yes, I agree. Private cloud systems are good, and a tiered approach can save money and effort.
- Netminder
