Question

Difficulty: HardResilience, High Availability, and Redundancy

A security architect is establishing high availability and resilience specifications for a mission-critical infrastructure deployment. Match each resiliency requirement or architectural challenge on the left with its corresponding technical mechanism or metric on the right.

  • Eliminating single points of failure across web servers while seamlessly preserving active user sessions during node outagesStateful Load Balancing with VIP failover
  • Defining the maximum tolerable duration of data loss measured in time prior to an unplanned service disruptionRecovery Point Objective (RPO)
  • Preventing data corruption caused by concurrent writes when heartbeat communication fails between cluster nodesNode Fencing / STONITH (Shoot The Other Node In The Head)
  • Providing storage-level disk redundancy allowing continuous operations despite a single drive failureRAID 5 / RAID 1 array configuration

Answer

The correct pairings are: 1. Preserving active user sessions across web server outages matches with Stateful Load Balancing with VIP failover; 2. Maximum tolerable duration of data loss matches with Recovery Point Objective (RPO); 3. Preventing data corruption during heartbeat failure matches with Node Fencing / STONITH; 4. Disk redundancy for continuous operation matches with RAID 5 / RAID 1 array configuration.
Each requirement directly aligns with its corresponding architectural control: RPO defines acceptable data loss interval; stateful load balancing preserves persistent connections across redundant nodes; STONITH node fencing prevents split-brain corruption in active-active/active-passive clusters; and RAID provides local disk fault tolerance.

Step-by-Step Solution

1
Analyze session-handling and network redundancy requirements.
Matched session preservation during server outage to Stateful Load Balancing with VIP failover.
Stateful load balancers track session state tables across cluster nodes, ensuring users remain logged in when traffic shifts.
2
Evaluate availability metrics for data recovery.
Matched data loss time threshold to Recovery Point Objective (RPO).
RPO measures acceptable data loss currency in units of time, whereas RTO measures acceptable duration of service disruption.
3
Analyze high-availability clustering split-brain safeguards.
Matched split-brain data corruption prevention to Node Fencing / STONITH.
When heartbeat lines fail, automated fencing mechanisms disable the disconnected node to guarantee exclusive write lock on shared storage.
4
Identify hardware-level redundancy controls.
Matched single-drive failure protection to RAID configurations.
RAID 1 (mirroring) and RAID 5 (striping with parity) provide hardware fault tolerance for storage volumes.

Key Concept

Resilience, High Availability, and Redundancy Mechanisms
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