Beginner LevelSystem Design & Architecture
What is a Single Point of Failure (SPOF) and how do redundant components mitigate risk?
❓ Interview Prompt: Explain Single Point of Failure (SPOF), fault tolerance, active-passive failover, multi-region redundancy, and eliminating SPOFs.
A Single Point of Failure (SPOF) is any component in a system whose individual failure will cause the entire system or application to crash:
Eliminating SPOFs Across System Layers:
1
DNS Layer: Use redundant multi-provider Anycast DNS.
2
Load Balancer Layer: Deploy dual active-passive load balancers with virtual IP failover (Keepalived / VRRP).
3
Application Tier: Maintain an auto-scaling group across multiple Availability Zones (AZs).
4
Database Tier: Configure multi-AZ primary/standby database failover.
Code Implementation Example
markdown
Eliminating Single Points of Failure:
[Vulnerable SPOF] [High Availability Redundant]
[Single DB] [Primary DB (AZ-1)]
│ │ (Async Sync)
(Fails = Crash!) ▼
[Standby DB (AZ-2)]💡Mitigating Single Points of Failure through active-standby multi-AZ database replication.
🎯 Interview Key Takeaway
Identify and eliminate all Single Points of Failure using redundant components across multiple Availability Zones.
#System Design#SPOF#High Availability#Fault Tolerance#Beginner
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