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Load Shedding

Deliberately drop, deny, or defer lower-priority load under overload so critical function stays within viable bounds.

Solution archetype #
605
Problem family
Fragility, Failure & Continuity Risk
Problem subfamily
Fault Containment & Bounded Service Loss

The Diagnostic Story

Symptom: Total demand has exceeded what the system can safely handle, and attempting to serve everything is degrading or about to collapse critical function. The queue is growing without bound. Essential paths are waiting behind nonessential ones. The system is treating all load as equally serviceable even though some of it is far more expendable than others.

Pivot: Make sacrifice explicit. Classify load by criticality, urgency, or recoverability, then deliberately drop, deny, defer, or deprioritize the lower-priority portion. The policy names what is shed, under what conditions, and how the shed load is handled, rather than letting collapse choose arbitrarily.

Resolution: Critical function remains viable because it retains capacity and queue growth is bounded. Shed load is handled predictably: rejected, expired, deferred, or rerouted with acknowledgment. The sacrifice is bounded by explicit fairness and safety rules rather than by whoever happens to fail first.

Reach for this when you hear…

[grid operator] “We drop residential blocks in rotation before the frequency deviation gets bad enough to trip generation, because losing a block is recoverable and losing a generator is not.”

[emergency triage nurse] “When the waiting room has forty people and I have two doctors, I have to triage or the critically ill patients die waiting behind the sprained ankles.”

[platform SRE] “During the incident we started rejecting recommendation requests and analytics writes so the checkout path could stay up.”

When This Archetype Applies

Complete catalog groundingAt least one sufficient condition set is fully represented by existing primes or domain-specific abstractions.

Total load exceeds safe handling capacity, and attempting to serve everything would degrade or collapse critical function.

Show the applicability expression

Applicability expression2 distinct conditions

Demand exceeds safe capacityandServing all collapses function
Algebraic12

groundedpartly groundedopen

2 conditions, all required.

2Required in every casenumbered 1–2

These hold no matter which pattern applies.

1

Demand exceeds safe capacity · grounded

Total demand, work, traffic, exposure, or obligation exceeds safe handling capacity.

2

Serving all collapses function · grounded · any one of 2

Attempting to serve all load would degrade or collapse critical function.

Other requirements and context (1)

Why these sit outside the expression

Solution feasibilityit describes whether the intervention can work, not whether the diagnostic problem exists.

  • Solution feasibilityLoads can be distinguished by criticality, reversibility, or service obligation.

2 of 2 conditions grounded.

Read the methodologyDownload the trigger-logic data

Abstractions this archetype builds on — directly (a source ingredient) or as a related pattern. Links follow the typed catalog namespace.

Built directly on (8)

  • Admission Control
  • Boundary: Defines system limits.
  • Graceful Degradation
  • Observability: Infer internal state externally.
  • Prioritization: Ordering competing claims on finite resources by a value or urgency metric to produce a ranked sequence of action under constraint, making explicit what gets done first and what does not get done at all.
  • Resource Management: Allocation of finite assets.
  • Selective Rejection
  • Threshold: Safe vs harmful levels.

Also references 9 related abstractions

  • Constraint: Limits possibilities to guide outcomes.
  • Coupling: Interdependence among subsystems.
  • Fail-Safe: Default to safe state on failure.
  • Fault Tolerance: Continue operating under failure.
  • Flow: Structured movement of energy, matter, or information.
  • Queueing: Organizes tasks into a waiting line based on arrival and service rates.
  • Resilience: Absorb shocks and adapt.
  • Scheduling: Organizing tasks over time.
  • Trade-offs: Balancing competing priorities.

Variants

Narrower or domain-specific specializations that share this archetype's core structure. Recognized variants are established; candidate variants are provisional.

Selective Rejection · risk or failure variant · recognized

Reject or drop lower-priority inflow to preserve viability for remaining work or users.

Editorial Notes

Problem Classification

Classification: Fragility, Failure & Continuity RiskFault Containment & Bounded Service Loss

Problem kernel: nonessential load cannot be shed to preserve critical service under stress

Rationale: Overload threatens whole-system collapse because lower-priority load cannot be shed while essential function remains active in a bounded degraded mode. Receiver saturation is the triggering condition, but the archetype's structural center is continuity triage: preventing nonessential demand from eliminating critical service, an explicit fault-containment cue.

Boundary considered: Capacity Scarcity & Resource ContentionAssimilation Saturation & Overload

Why this classification prevailed: Fault containment governs preserving essential degraded service by shedding noncritical function; assimilation overload governs the receiver crossing its capacity ceiling before service priorities are separated.

Review outcome: Adjudicated after independent review; high confidence.