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HotSpareScenario

Reliability scenarios · Implementation: mlsysim/engine/scenario_definitions/reliability.py.

Construct this scenario with keyword inputs. The fields below show the types and defaults declared by this class.

spare_devices held idle beside the job in failures, priced at device_hour_rate.

The spare pays off when it shortens every recovery by more than breakeven. Added 2026-10-20.

Notes

Equation: Use the dimensional products, ratios, or selection rules documented on the calculated properties below.

Assumptions: Daily spare rental is compared with saved billed device-time on every modeled failure; all affected devices benefit from the same recovery reduction.

Excludes: Placement constraints, failure overlap, and service-value pricing beyond rental cost are absent.

References

Derivation: the calculated properties below state their defining arithmetic and units. They are scenario accounting or input-selection rules, not independently measured relationships.

Examples

>>> from mlsysim import Scenarios
>>> case = Scenarios.HotSpareNode10K
>>> print(f"{case.spare_cost_per_day.m_as('USD'):.1f} USD")
384.0 USD

Attributes

Name Description
breakeven Recovery time that each spare intervention must save to cover daily spare cost.
device_hour_rate
failures
spare_cost_per_day Rental cost of keeping every spare idle for a day. Equation: ``spare_devices *
spare_devices
value_per_minute Daily rental value of removing one minute from each recovery. Equation: expected daily

failures

Type: Any.

Declared default: required.

spare_devices

Type: int.

Declared default: required.

device_hour_rate

Type: Quantity.

Declared default: required.

spare_cost_per_day

engine.scenario_types.HotSpareScenario.spare_cost_per_day

Rental cost of keeping every spare idle for a day. Equation: spare_devices * device_hour_rate * one_day. Units: USD per stated day; no opportunity-value adjustment is included.

value_per_minute

engine.scenario_types.HotSpareScenario.value_per_minute

Daily rental value of removing one minute from each recovery. Equation: expected daily failures times affected devices times hourly price times one minute. Units: USD per stated day.

breakeven

engine.scenario_types.HotSpareScenario.breakeven

Recovery time that each spare intervention must save to cover daily spare cost. Equation: spare_cost_per_day / value_per_minute * one_minute. Units: seconds; the modeled avoided loss must be positive.

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