Complex System Troubleshooting and Incident Diagnosis Questions

Tests systems thinking and approaches for diagnosing problems that span multiple components services layers or domains and present multiple related symptoms. Candidates should show how they map interdependencies prioritize which symptoms to address first generate and test hypotheses correlate telemetry across logs metrics and traces and distinguish root causes from secondary effects. The topic includes using instrumentation and monitoring to isolate failures reproducing issues in controlled environments understanding cascading failures and failure modes across networking storage database and application layers and applying mitigations rollbacks or fixes while minimizing user impact. Candidates should also describe incident communication documentation and post incident analysis to prevent recurrence.

HardTechnical

25 practiced

A storage array shows intermittent read latency spikes that cause database queries to timeout. Propose immediate runtime mitigations (IO scheduling changes, redirecting load, throttling clients), a forensics plan to capture SAN/array logs and SMART/health data without worsening the issue, and a long-term remediation and testing plan including failover procedures and capacity validation.

HardTechnical

21 practiced

A set of records in a critical table were corrupted and this corruption propagated to downstream services. Describe in detail how you would conduct a forensic investigation: establishing a reliable timeline, preserving evidence (snapshots, logs, backups), determining scope and origin of corruption, reconstructing events across services, coordinating fixes and rollbacks, and documenting the chain-of-custody and conclusions for compliance purposes.

HardSystem Design

18 practiced

Design a business continuity and failover strategy for a multi-region relational database used by global customers with requirements: RTO = 1 hour, RPO = 5 minutes. Describe the replication topology, failover automation, consistency model trade-offs, DNS/service discovery changes, backup implications, and testing strategy to validate the plan.

EasyTechnical

21 practiced

You are handing over on-call to a colleague at shift change. Draft the essential information you must convey in the handover note and verbally: active incidents, degraded systems, transient alerts to watch, scheduled maintenance, outstanding action items, key runbook locations, and known workarounds. Explain why each piece of information matters and what you would include as 'must escalate' items.

MediumTechnical

18 practiced

You receive simultaneous alerts: the database shows elevated connection count and the application shows increased 5xx errors. Describe how you would generate and test hypotheses to determine causality (is the DB causing app errors or are app retries causing DB saturation?). Include specific queries, metrics, and controlled mitigation steps to test each hypothesis.

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