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TechnologyGenerated accuracy model review: 2026-05-06
VM Sizing Calculator accuracy and testing
This page documents how Calwarden builds trust for this calculator: source notes, regression-style default tests, limitations, assumptions, unit handling, rounding, and visible change history.
Formula source
- Total vCPU = instances * vCPU per instance * headroom factor. Total memory = instances * memory per instance * headroom factor. Hosts = ceil(max(total vCPU / usable host vCPU, total memory / usable host memory)).
Test cases
Default input regression check
Generated from the checked-in default inputs and calculate function.
Inputs
- Application Instances: 24
- vCPU per Instance: 2 vCPU
- Memory per Instance: 6 GB
- Headroom: 25%
- vCPU per Host: 32 vCPU
- Memory per Host: 128 GB
- Target Utilization: 75%
Expected outputs
- Recommended Hosts: 3
- Total vCPU Needed: 60 vCPU
- Total Memory Needed: 180 GB
- Limiting Resource: CPU
Known limitations
- This page documents the checked-in calculator logic and does not certify results for every real-world edge case.
- Use the result as a planning estimate unless the calculator page states a stricter purpose.
Assumptions
- No oversubscription beyond target utilization is modeled.
- Storage, network, licensing, and affinity rules are not included.
- Inputs remain local.
Unit handling
- Application Instances accepts numeric values.
- vCPU per Instance accepts values in vCPU.
- Memory per Instance accepts values in GB.
- Headroom accepts values in %.
- vCPU per Host accepts values in vCPU.
- Memory per Host accepts values in GB.
- Target Utilization accepts values in %.
- Total vCPU Needed is displayed in vCPU.
- Total Memory Needed is displayed in GB.
Rounding rules
- Number displays use up to 2 decimal places in the calculator UI.
- Input precision follows configured step values where provided.
Version history
1.0.0 - 2026-05-06
Generated accuracy and testing page from the current vm-sizing-calculator calculator definition.
Change log
2026-05-06
Published default regression test documentation and metadata fallbacks for VM Sizing Calculator.
Calculator transparency
Accuracy pages are generated from checked-in calculator definitions and can be upgraded with curated review metadata over time.