Performance Fundamentals and Troubleshooting Questions

Core skills for identifying, diagnosing, and resolving general performance problems across applications and systems. Topics include establishing baselines and metrics, using monitoring and profiling tools to determine whether issues are CPU bound, memory bound, input output bound, or network bound, and applying systematic troubleshooting workflows. Candidates should be able to prioritize fixes, recommend temporary mitigations and long term solutions, and explain when to escalate to specialists. This canonical topic covers general performance awareness, common diagnostic tools, and basic remediation approaches for slow systems and resource exhaustion.

HardTechnical

0 practiced

A recent deployment caused performance regressions only in Region A. Describe an investigation plan to determine whether the regression is due to the deployment, regional infra differences, or traffic profile differences. Include what metrics/logs to compare and how to test hypotheses with minimal user impact.

MediumTechnical

0 practiced

You are asked to craft a runbook for a recurring incident where CPU load spikes every hour on the hour. Write the steps to triage, temporary mitigations (one-line each), and a prioritized list of long-term investigations to find the root cause.

MediumTechnical

0 practiced

You see the following iostat sample for a problematic server (columns: rrqm/s wrqm/s r/s w/s rsec/s wsec/s await)

Device: sdar/s: 0.1 w/s: 120 rsec/s: 0 wsec/s: 307200 await: 12.5

Interpret this data: what does it say about IO pattern and potential problem? What next diagnostic commands would you run and why?

EasyTechnical

0 practiced

Given a Linux server showing high 'load average' values, list and describe the sequence of quick checks and commands you run in the first 10 minutes to determine whether the problem is CPU bound, IO bound, memory bound, or network bound. Include specific commands and what you'd look for in their output.

MediumTechnical

0 practiced

Write a short Bash script or systemd timer configuration to perform log rotation for an application that produces large JSON logs, ensuring rotations do not lose logs and old logs are compressed. Explain assumptions and atomicity considerations.

Unlock Full Question Bank

Get access to hundreds of Performance Fundamentals and Troubleshooting interview questions and detailed answers.

Join thousands of developers preparing for their dream job.