Redundancy & Fault Tolerance¶

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Solutions that preserve service when parts fail by duplicating capability, diversifying failure modes, or providing independent alternate paths.

40 mechanisms across 5 solution archetypes in this solution family. A mechanism inherits the primary family of the archetype it instantiates; family is about the move the solution makes, not the domain where it originated.

Adaptive Reconfiguration¶

When ordinary control fails, reorganize internal structure or strategy so the system can remain viable under changed conditions.

6 mechanisms · View full solution archetype

Dynamic Team Reassignment — Pulls people and roles out of their normal assignments and re-slots them onto the fronts that need them, on a pre-agreed rule, when the standing staffing arrangement can no longer hold.
Emergency Governance Mode — Temporarily shifts authority and escalation into a crisis regime — with the trigger that switches it on and the sunset that switches it off both fixed in advance — so decisions can be made fast without the shift becoming permanent.
Mission Reprioritization Protocol — Re-ranks what the system is trying to achieve when the old priorities start producing harm, dropping and promoting objectives against an explicit measure of what must be preserved.
Organizational Restructuring After Crisis — Redraws reporting lines, roles, and coordination structure into a durable new arrangement after a crisis exposes the old structure as the thing that failed — and captures why, so the lesson outlives the reorg.
Reconfigurable Manufacturing Cell — A production cell built from modular, movable, re-linkable machines so the floor can be physically rearranged for a new product mix instead of being torn out and rebuilt.
Service Topology Rewiring — Rewires a running system's live service dependencies and routing into a stability-preserving topology when autoscaling and playbooks fail — reversibly, so it can be rolled back if the new shape is worse.

Common-Mode Failure Analysis¶

Identify shared dependencies that could cause supposedly independent backups or safeguards to fail together.

8 mechanisms · View full solution archetype

Backup Independence Test — Exercises backup paths under a shared dependency outage or simulated common cause to verify whether they are genuinely independent.
Common-Cause FMEA — Extends failure mode and effects analysis by asking which single causes could defeat multiple redundant elements or controls at once.
Correlated Risk Register — Records shared exposures, affected redundant paths, severity, mitigation owner, test evidence, and residual risk acceptance.
Credential and Infrastructure Dependency Audit — Checks whether backup systems, emergency roles, and alternate channels still depend on the same identity provider, network, power source, cloud region, or access authority.
Diverse Vendor Review — Assesses whether vendor diversity is real across ownership, infrastructure, code lineage, hosting, support, credentials, and failure response capability.
Fault Tree with Common-Cause Branching — Decomposes a top-level failure through logic gates to its basic causes, then adds shared-cause branches so a single event feeding several 'independent' paths becomes visible.
Supply-Chain Dependency Review — Traces whether alternate suppliers, logistics routes, components, or raw materials share sub-tier vendors, regions, infrastructure, labor constraints, or regulatory chokepoints.
Tabletop Cascade Exercise — Simulates a shared failure cause and asks how redundant paths, teams, authorities, and recovery plans respond when they are stressed together.

Diverse Functional Redundancy¶

Provide multiple distinct ways to fulfill the same function so common-mode failure is less likely.

9 mechanisms · View full solution archetype

Alternate Communication Channels — Maintains distinct channels such as SMS, radio, phone trees, email, in-person notice, or public posting so communication can continue when one medium fails.
Diverse Data Source Triangulation — Combines independent data sources with different collection methods or bias profiles so the same informational function is not dependent on one fragile source.
Diverse Implementation Voting — Compares outputs from independently designed implementations so one flawed implementation is less likely to determine the final result alone.
Diverse Supplier Network — Uses suppliers with different geographies, ownership, logistics, technologies, or input sources to reduce correlated supply failure.
Heterogeneous Technology Stack — Uses different technical implementations for critical capability so a single software defect, vendor outage, or platform assumption is less likely to disable all paths.
Independent Safety System — Provides a separate safety path using different sensing, control, energy, or actuation logic so one design flaw or dependency is less likely to defeat all protection.
Manual Fallback Workflow — Preserves a function through a human or paper-based process when the digital, automated, or centralized path is unavailable.
Mixed-Channel Service Delivery — Offers the same service through different channels such as online, phone, physical office, outreach worker, kiosk, or partner organization.
Multi-Modal Transport Plan — Uses different transport modes such as road, rail, air, water, walking, or cycling to preserve movement of people or goods when one mode is disrupted.

Fault-Tolerant Operation¶

Keep operating despite partial failure by detecting, isolating, masking, bypassing, or compensating for failed components.

9 mechanisms · View full solution archetype

Bypass Routing — Keeps a critical flow moving by sending work, traffic, or authority along an alternate path around the failed element instead of through it.
Degraded Operation Mode — Preserves the most important function at deliberately reduced capacity, precision, feature scope, or automation when the full-service posture can no longer be sustained.
Error Correction — Masks corruption by adding structured redundancy to a single data stream so that a bounded number of errors can be detected and reconstructed to the correct value in place.
Fault Detection and Diagnosis — Makes a local failure observable and names it — sensing that something is wrong and classifying which component failed and how, so the right continuation response can be chosen.
Fault Isolation — Draws a boundary around a faulty element so its damage cannot spread to healthy parts, then readmits it only once it is verified sound.
Manual Continuity Workaround — Keeps a critical function going through a rehearsed human procedure when the normal automated path fails, then reconciles the manual work back into the system on recovery.
Redundant Voting — Runs the same job on multiple independent replicas and trusts the majority, so a minority of faulty units is outvoted rather than obeyed.
Self-Healing Repair Loop — Closes the loop on a fault autonomously — detect, apply a bounded repair, verify recovery, and reintegrate — restoring capacity without waiting for a human.
Service Continuity Runbook — An operational document that names the protected function and choreographs the whole fault response — detection, isolation, continuation, escalation, and recovery — with roles and authority made explicit.

Redundant Backup Provisioning¶

Provision duplicate capacity or components so failure of one does not eliminate critical function.

8 mechanisms · View full solution archetype

Backup Power System — Provides alternate electrical capacity for critical functions when the primary power source fails.
Backup Supplier Contract — Maintains an alternate source for critical inputs when the primary supplier cannot deliver.
Deputy Role Assignment — Names a prepared alternate actor who can perform a critical responsibility when the primary actor is absent or impaired.
Emergency Reserve Stock — Stores critical materials, funds, equipment, or supplies for use when ordinary supply is interrupted.
N+1 Redundancy Rule — Sizes redundancy by provisioning one spare unit beyond the number needed to carry peak load, so any single unit can fail without dropping the function below its requirement.
Redundant Server — Duplicates computing capacity so a service, application, or data function can continue after one server fails.
Spare Part Stock — Keeps replacement parts available so a failed physical component can be replaced without waiting for external procurement.
Standby Team Roster — Keeps a prepared group available to cover a critical operation during absence, overload, or incident response.