How much storage growth should I plan for?
Start with the amount of data you need to keep, not the capacity printed on your drives. Compare measurements from several dates to estimate growth. A one-off migration is different from a photo library or backup set that keeps growing every month.
The planner applies a constant annual percentage. At 20% annual growth, 10 TB becomes 12 TB after one year and 14.4 TB after two. That is a scenario, not a forecast that your future use will follow the same curve. Try a slower and faster case if your plans are uncertain.
Enter retained snapshots or backups in the data requirement when they belong on this storage. The separate backup budget is money set aside for backup, not an automatic extra copy of the projected data.
What does the first shortfall year mean?
The planner compares projected data with capacity after your operating reserve. Crossing that line means the plan uses space you intended to leave free. It doesn't mean the hardware fails or that the filesystem becomes full on January 1 of that year.
A result that covers the whole horizon means only that it covers the assumptions you entered. Capacity is modeled from equal-size drives and the selected redundancy. Filesystem metadata, ZFS allocation details, and an existing pool's history need a more specific estimate, such as the ZFS capacity calculator.
Reserve is a planning choice, not a universal safe-fill threshold. Keep enough room for the operations your system needs, and check the storage platform's guidance rather than copying an unexplained percentage.
What belongs in the total cost?
| Input | Use a figure that represents |
|---|---|
| Hardware | The drives and enclosure included in this purchase |
| Power | Average draw for the complete system, not the drives' label ratings alone |
| Electricity rate | The rate you expect to pay in the same currency as the other costs |
| Replacement reserve | A budget allowance, not a prediction of which disks will fail |
| Backup budget | The separate cost you choose to allow for backup |
For a continuously running 50 W system, the simple annual energy calculation is 438 kWh: 0.05 kW multiplied by 8,760 hours. Multiply that by your electricity rate to understand why a small continuous load can matter over several years. The live estimate uses your inputs, not a current electricity or hardware price feed.
What should I verify before buying?
The model leaves out labor, cooling, taxes, migration costs, cloud retrieval charges, and currency conversion. It does not predict performance or reliability. Check quotes and measured power against the scenario before using the total as a budget.
Capacity and redundancy also cannot establish that a backup exists or restores. Verify a separate copy and a restore path; CISA's ransomware guide explains why backups need regular recovery tests.
The calculation runs in your browser. A shared configuration exposes the inputs in its URL, so treat a shared link as a readable plan rather than private storage.