Estimator Form
Example Data Table
| Scenario | Mode | Data | Speed | Reductions | Estimated Time |
|---|---|---|---|---|---|
| Nightly media archive | Full | 2.5 TB | 350 MB/s | 20% compression, 10% dedup | 2h 57m |
| Cloud sync change set | Incremental | 7 TB total, 8% changed | 1.2 Gbps | 15% compression, 5% dedup | 1h 06m |
| Database protection copy | Differential | 1.2 TB total, 25% changed | 220 MB/s | 35% compression, 0% dedup | 31m |
| Dual-target compliance job | Mirror | 4 TB | 500 MB/s | 0% compression, 0% dedup, 2 copies | 5h 32m |
Formula Used
1. Included data for this run = total data × mode factor.
2. Mode factor is 1.00 for full and mirror jobs. For incremental or differential jobs, it equals changed data percent ÷ 100.
3. Data after reductions = included data × (1 − compression savings) × (1 − dedup savings).
4. Protected data written = reduced data × number of copies.
5. Effective throughput = nominal throughput × utilization × (1 − protocol overhead) × (1 − encryption overhead).
6. Transfer time = protected data written ÷ effective throughput.
7. Total time = transfer time + verification time + retry allowance + initialization time.
Compression and dedup are treated sequentially. Verification and retries are modeled as percentages of transfer time for practical planning.
How to Use This Calculator
- Choose the backup mode that matches the job you plan to run.
- Enter total dataset size and select the correct storage unit.
- Add changed data percent for incremental or differential estimates.
- Enter nominal transfer speed and the matching throughput unit.
- Adjust utilization, protocol overhead, and encryption overhead to reflect real conditions.
- Enter compression and dedup savings if your platform reduces written data.
- Add verification, retry allowance, initialization minutes, and backup window hours.
- Optionally provide a start date and time to estimate completion.
- Submit the form to show results above the form and review the Plotly chart.
- Use the CSV and PDF buttons to export the result summary.
FAQs
1. What does this estimator measure?
It estimates how long a backup run may take after accounting for dataset size, changed data, throughput, overhead, reduction methods, verification, retries, and setup time.
2. Why is effective throughput lower than nominal speed?
Real backup jobs rarely sustain link speed. Utilization gaps, encryption, protocol chatter, storage latency, and system contention reduce the throughput available to payload data.
3. When should I use changed data percent?
Use it for incremental and differential jobs. It represents the share of the full dataset that actually changed and must be processed during the current run.
4. How are compression and dedup handled?
The calculator applies compression savings first, then dedup savings on the reduced result. That sequence gives a practical estimate of how much data is written.
5. Does this tool estimate cloud backups too?
Yes. It works for local, network, and cloud protection jobs as long as you enter realistic throughput, overhead, utilization, retry, and verification assumptions.
6. What is retry allowance?
Retry allowance is extra time reserved for retransmissions, failed chunks, or interrupted sessions. It helps planners avoid understating real production backup windows.
7. Why include initialization minutes?
Many jobs spend time building catalogs, scanning files, opening sessions, or negotiating targets before payload transfer begins. Initialization captures that fixed startup delay.
8. Can I use this for restore planning?
It is designed for backup estimates, but you can adapt it for restores by entering restore throughput, validation overhead, and copied data volume for the recovery job.