Backup Footprint
{{ totalStorageReadable }}
Coverage horizon {{ coverageHorizon }}
{{ totalBackups }} backup copies Incremental {{ incrementalSizeReadable }} Full {{ fullSizeReadable }} Raw {{ totalStorageRawReadable }} Savings {{ dedupeSavingsLabel }} {{ changeRateLabel }}
copies
copies
copies
copies
{{ params.changeRatePercent }}%
:1
:1
{{ params.dedupePercent }}%
Tier Frequency Copies Per backup Storage (raw) Storage (net) Coverage Copy
{{ row.tier }} {{ row.frequency }} {{ row.copies }} {{ row.sizePerBackup }} {{ row.rawStorage }} {{ row.netStorage }} {{ row.coverage }}
Total {{ totalBackups }} {{ totalStorageRawReadable }} {{ totalStorageReadable }} {{ coverageHorizon }}
Planner Notes

Use these observations to prioritise storage remediation or policy tweaks.

  • {{ line }}

No insights yet—adjust retention or compression to surface guidance.


                
Configure retention targets to estimate backup storage footprint and coverage.

Introduction:

Backup retention schedules are layered sets of incremental and full copies that preserve recent changes and keep longer history as space allows. Many teams use them to balance recovery speed, coverage length, and storage cost.

The model helps you reason about grandfather father son backup rotation planning with concrete numbers. You provide typical change volume and a full copy size, then choose how many daily, weekly, monthly, and yearly copies to keep. The result estimates storage after compression and deduplication and reports how far back you can roll.

A common setup might keep two weeks of incrementals with four weekly fulls and a year of monthly fulls. With modest compression and a small growth rate, the footprint often lands well below a raw sum and the longest window still reaches many months.

Results depend on your inputs and policy choices, so revisit them whenever data growth accelerates or retention targets change. Use consistent units and comparable periods so trends are clear across reviews.

Technical Details:

The planner models two quantities: the size of each stored backup and how many copies you retain over a time window. Incremental backups capture changed data since the last point, while full backups capture the entire dataset. Compression reduces each backup before storage, and global deduplication removes repeated blocks across all copies. Grandfather–Father–Son (GFS) is treated as a layered policy of daily, weekly, monthly, and yearly tiers.

For each tier, an effective per‑backup size is computed from the base measurement and a compression ratio. A simple growth factor inflates sizes for older tiers to reflect increasing data volume over time. Net storage is then the raw tier total after a deduplication savings percentage is applied.

Results include totals for raw and net storage across all tiers, the number of stored copies, and the maximum protection window (“coverage horizon”) implied by your daily, weekly, monthly, and yearly selections. Comparisons are most meaningful when the same units and growth assumptions are used between runs.

Sincbytes = vincvalue×1024k Sfullbytes = vfullvalue×1024k Eincbytes = SincbytesCincratio Efullbytes = SfullbytesCfullratio GF(d,g) = 1+(g/100)×d30×12 Ltierbytes = Ebasebytes×GF Rtierbytes = Ltierbytes×n Ntierbytes = Rtierbytes×(1D/100)
Symbols and units used in the model
Symbol Meaning Unit/Datatype Source
vinc, vfull Entered size values MB, GB, TB Input
k Binary exponent for unit 2 for MB; 3 for GB; 4 for TB Constant
Cinc, Cfull Compression ratios dimensionless (≥ 1) Input
g Monthly change rate percent (0–50) Input
d Coverage days per tier days Derived
n Copies retained per tier count Input
D Global dedupe savings percent (0–80) Input
Ebase Effective size after compression bytes Derived
R, N Raw and net storage per tier bytes Derived
Worked example. Inputs: incremental 60 GB with compression 2.0, full 500 GB with compression 1.5, daily 14, weekly 4, monthly 12, yearly 2, change rate 5%, dedupe 30%. Then:
EincGB = 60/2.0=30 GB EfullGB = 500/1.5333.3 GB GF(14,5) = 1+(5/100)×1430×121.0117 LdailyGB = 30×1.011730.35 GB RdailyGB = 30.35×14425 GB NdailyGB = 425×(10.30)297.5 GB

Repeat the same steps for weekly, monthly, and yearly tiers to obtain raw and net totals and the longest coverage window.

Units, precision & rounding

  • Binary multiples (1024) are used for MB, GB, TB; outputs scale through EB.
  • Displayed precision is 0 decimals for values ≥ 100 or bytes, otherwise 1 decimal place.
  • Coverage uses 14‑day, 8‑week, and 18‑month cutovers to show days, weeks, months, or years.
  • Months are approximated as 30 days; years as 365 days.

Validation & bounds

Inputs and validation constraints
Field Type Min Max Step/Pattern Placeholder/Notes
Daily incremental size number + unit 0 0.1; MB/GB/TB Pre‑compression change volume
Full backup size number + unit 0 0.1; MB/GB/TB Pre‑compression full footprint
Daily incrementals retained integer 0 1 Copies
Weekly full backups integer 0 1 Copies
Monthly full backups integer 0 1 Copies
Yearly archives integer 0 1 Copies
Monthly change rate slider 0 50 1 Percent
Full compression number 1 0.1 Ratio
Incremental compression number 1 0.1 Ratio
Global dedupe savings slider 0 80 1 Percent
Preset select Custom, GFS, Compliance, Cloud snapshot Applies tested recipes

I/O formats

Inputs and outputs
Input Accepted Families Output Encoding/Precision Rounding
Sizes & counts Numeric fields with units Table totals & coverage Binary multiples (B–EB) 0 or 1 decimal as above
Exports CSV, DOCX, JSON (optional) Structured breakdown Locale‑neutral text & JSON Stable formatting

Networking & storage behavior

Computation, exports, and charting are performed in the client. No data is transmitted to a server or stored beyond your explicit file downloads.

Performance & determinism

Time and memory scale with the number of tiers (four fixed layers). The calculator is deterministic: identical inputs produce identical outputs.

Security considerations

  • Inputs are numeric and constrained; fields reject negative values.
  • Clipboard and download actions require user gestures permitted by the browser.
  • Avoid embedding sensitive environment details in exported documents.

Assumptions & limitations

  • Growth is linear with average age per tier; real data may grow unevenly. Heads‑up
  • Months are fixed at 30 days and years at 365 days.
  • Dedupe is modeled as a single global percentage across all tiers.
  • Compression ratios are constant per backup type.
  • Only MB, GB, and TB inputs are supported.
  • Coverage horizon uses the maximum tier window, not cumulative reach.
  • Zero or empty inputs suppress results until a valid configuration exists.
  • Charts omit tiers with zero copies or non‑finite sizes.

Edge cases & error sources

  • Very large sizes can display in PB/EB; verify units before sharing.
  • Compression set below 1 is clamped to 1 by the model.
  • Dedupe values above 80% are clamped to 80%.
  • Change rate at 0% removes growth effects; coverage still applies.
  • All retention counts at 0 yield no results and no charts.
  • Mixed units across runs reduce comparability of trends.
  • Clipboard operations may fail if blocked by browser permissions.
  • Downloads may be intercepted by pop‑up or download blockers.
  • Rounding can hide small differences at high totals.
  • Switching presets overrides current values until changed again.

How‑to:

Backup retention sizing from inputs to interpreted totals.

  1. Choose a preset or select Custom.
  2. Enter a daily incremental size and unit MB/GB/TB.
  3. Enter a full backup size and unit.
  4. Set copies for daily, weekly, monthly, and yearly tiers.
  5. Adjust change rate, compression, and dedupe if needed.
  6. Review storage totals and the coverage horizon; export if required.

Example: 60 GB incremental, 500 GB full, 14 daily, 4 weekly, 12 monthly, 2 yearly, 5% growth, 30% dedupe. The model returns multi‑terabyte raw storage and a lower net footprint with a months‑long window.

  • Tip: Keep units consistent between planning sessions so comparisons remain valid.

FAQ:

Is my data stored?

No. Calculations, charts, and exports are generated locally. Nothing is sent to a server; files save only when you choose to download.

Clipboard and download permissions depend on your browser.
How accurate is the estimate?

The model applies constant compression, a global dedupe percentage, and linear monthly growth by average age. It is a planning estimate, not a capacity guarantee.

Which units are used?

Binary multiples are used for conversion and display. Values scale from bytes through exabytes, with 0 or 1 decimal shown as described above.

Can I use it offline?

Once the page is open, calculations and exports work without a network connection. Refreshing may require network access depending on how the page was loaded.

How do I plan GFS 7 4 12 2?

Select the matching preset or set 7 daily incrementals, 4 weekly fulls, 12 monthly fulls, and 2 yearly archives. Adjust compression, growth, and dedupe to fit your environment.

What does the coverage horizon mean?

It is the longest protection window implied by your tiers. For example, 12 monthly fulls yield roughly one year, even if daily or weekly tiers are shorter.

How do I share results?

Use CSV for tables, JSON for programmatic use, or DOCX for a formatted brief. Clipboard copy is available for quick pastes into tickets or notes.

Are there licensing or costs?

No licensing terms or pricing are included in this package. Treat the output as informational planning material unless governed by your internal policies.

Troubleshooting:

  • No results shown — ensure sizes are greater than zero and at least one tier has copies.
  • Chart is blank — switch to the chart tab after results exist, then resize the window once.
  • Copy failed — your browser may block clipboard writes; try the download option.
  • Download did nothing — allow downloads or disable blockers and try again.
  • Tooltips missing — toggle presets once to re‑initialize help bubbles.
  • Numbers look too large — verify compression ratios are ≥ 1 and dedupe is reasonable.

Advanced Tips:

  • Tip Use presets as a starting point, then nudge growth and dedupe to mirror your estate.
  • Tip Track results monthly using the same inputs to spot trend inflections early.
  • Tip When storage is tight, trim weeklies before monthlies to preserve long history.
  • Tip If growth accelerates, raise compression or dedupe assumptions conservatively.
  • Tip Keep one scenario with zero dedupe as a worst‑case bound for procurement.
  • Tip Export JSON alongside CSV so future automation can consume the same plan.

Glossary:

Incremental backup
A copy containing only data changed since the last backup.
Full backup
A complete copy of the protected dataset.
Retention
The number of copies kept for a given tier.
Compression ratio
Factor by which data size is reduced; ≥ 1.
Global dedupe
Cross‑copy block elimination expressed as a percentage.
Coverage horizon
The longest look‑back period your retention policy provides.