Fault Tree Analysis

TOP EVENT

CLUSTER FAILURE: ≥50% of render nodes offline simultaneously.

This is not a philosophical question. It is a boolean condition evaluated every cycle. When true, the pipeline halts. When false, it runs.

GATE LOGIC

Fault trees decompose failure into gates. Each gate is a logical operator. Each branch is a physical cause.

TOP EVENT: CLUSTER_FAILURE
     │
     ├─ OR Gate: Any of the following triggers TOP
     │
     ├─┬─ POWER_FAILURE (AND gate)
     │  │   ├─ PSU_A_FAIL
     │  │   └─ PSU_B_FAIL
     │  │
     │  ├─ COOLING_FAILURE (OR gate)
     │  │   ├─ CRAC_UNIT_DOWN
     │  │   └─ HOTSPOT_TEMP > 85°C
     │  │
     │  └─ NETWORK_PARTITION (AND gate)
     │      ├─ SWITCH_A_DOWN
     │      └─ SWITCH_B_DOWN
     │
     └─ SOFTWARE_CASCADE (OR gate)
         ├─ DRIVER_CRASH
         └─ QUEUE_MANAGER_HANG

Probability: P(TOP) = 1 − ∏(1−P_i) for OR gates; P(TOP) = ∏P_i for AND gates.

SVG DIAGRAM

Diagram: Top-event decomposition. Ellipse = TOP, Rectangles = Gates, Circles = Basic Events. Lines = causal edges.

CUT SETS

A minimal cut set is the smallest combination of basic events that guarantees TOP.

• Cut Set 1: {PSU_A, PSU_B}
• Cut Set 2: {CRAC} ∪ {HOT}
• Cut Set 3: {SW_A, SW_B}
• Cut Set 4: {DRV} ∪ {QM}

Mitigation: Eliminate any single member of a Cut Set to break the path.

DATA TWIN

Machine-readable gate definitions for agent consumption.

/fault-tree-analysis.json