The Cell hardware has only been tested with hard drives up to 8TB. In fact, a low-energy board like the one inside the Cell may start malfunctioning managing more storage due to hardware limitations.
In order to be safe and not have users connect an excessively large drives with unknown results, we have a boundary at 8TB of physical storage, corresponding to maximum of 4TB of cloud space. This means that regardless of how much physical storage you provide to the Cell, it will not increase beyond 4TB of extra space. This will help in keeping the network stable and efficient.
No matter which Cell or you own (512GB, 1TB or any variation with SaaS or extra storage), the Cell will physically only accept up to a maximum 8TB external drive connected to it in order to further expand the total space added by the Cell up to 4TB with anything beyond that being assigned extra cloud space, not physical space.
Some examples of maximum storage possibilities per Cell:
- Cell 512GB + 8TB external drive = 4TB total
- Cell 1TB + 8TB external drive = 4TB total
- Cell 4TB + 8TB external drive = 7TB total (4TB with +3TB cloud storage)
- Cell 8TB + 8TB external drive = 11TB total (4TB with +7TB cloud storage)
In the future, if we have evidence and data that the Cell is stable with more than 8TB of external storage attached per Cell, we will raise the limit. Right now the best way to go beyond 4TB is to use another Cell.