Backups
Backup capacity planning: estimate storage from change rate and retention
Backup capacity planning combines protected data size, growth, change rate, retention, full/incremental behavior, compression or deduplication, temporary workspace, and restore headroom. Buying backup storage equal to today’s live disk size rarely covers a useful retention window.
Measure protected bytes, not allocated disk
Inventory actual database dumps, files, VM/application data, configuration, and other material you intend to retain. A 500 GB VPS with 80 GB used may not need 500 GB per backup, while an application with generated database dumps can briefly need more than live data.
Exclude reproducible caches/build artifacts unless recovery really depends on them.
Estimate daily change and growth
Track changed data over representative weekdays, weekends, imports, release cycles, and month-end jobs. Use measured compression and deduplication ratios from your own data.
Add business growth and new workload expectations to the horizon.
Model retention and temporary operations
Full-plus-incremental schedules, synthetic full operations, pruning, verification, and restores can require extra workspace. Keep headroom so the repository does not fail while deleting old copies.
Set alerts before capacity reaches the point where a new backup cannot complete.
Reforecast from repository history
Monthly review of source size, backup size, daily growth, oldest point, and capacity runway provides better purchasing evidence than one initial spreadsheet. Keep the same metrics after major application imports or retention changes so the forecast reflects how the repository actually behaves under new data patterns.
- Measure actual protected data.
- Track change rate.
- Include retention/workspace.
- Monitor capacity runway.