Backend Engineering & Performance Topics
Backend system optimization, performance tuning, memory management, and engineering proficiency. Covers system-level performance, remote support tools, and infrastructure optimization.
Scalability Analysis and Bottleneck Identification
Techniques for analyzing existing systems to find and prioritize bottlenecks and to validate scaling hypotheses. Topics include profiling and benchmarking strategies instrumentation and monitoring of latency throughput error rates and resource utilization; identification of common bottlenecks such as database write throughput central processing unit saturation memory pressure disk input output limits and network bandwidth constraints; designing experiments and load tests to reproduce issues and validate mitigations; proposing incremental fixes such as caching partitioning asynchronous processing or connection pooling; and measuring impact with clear metrics and iteration. Interviewers will probe the candidate on moving from observations to root cause and on designing low risk experiments to validate improvements.
System Monitoring and Performance Tuning
Operational monitoring and continuous tuning of system and infrastructure resources to maintain performance and reliability. Topics include key system health and performance metrics such as central processing unit usage memory utilization disk input output and latency network bandwidth process counts system load latency and throughput and queries per second, establishing baselines and normal ranges, anomaly detection and root cause triage, instrumentation and metric collection for system health, reading monitoring dashboards and recognizing common failure patterns, interpreting system logs and using diagnostic commands and tools, setting alert thresholds and prioritization and escalation pathways, capacity planning and remediation steps, resource tuning to remove bottlenecks, and knowing when to escalate to deeper engineering investigation. Candidates should be able to connect observed symptoms to likely causes describe basic troubleshooting workflows and propose mitigation and prevention measures.
Performance Fundamentals and Troubleshooting
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.
Server Side Asynchronous Programming
Asynchronous and concurrent programming as applied to backend systems, including event loop models, thread pools, futures and promises, asynchronous I O, streaming, and reactive frameworks. Covers Node dot js event loop and streaming APIs, Java threading models and reactive libraries such as Project Reactor or RxJava, Python asyncio and multiprocessing versus multithreading trade offs, handling blocking operations, backpressure and flow control, and patterns to structure scalable non blocking servers. Candidates should demonstrate the ability to reason about throughput, latency, resource contention, and appropriate concurrency models for server workloads.
System Resource Management and Monitoring
Monitor and manage operating system and hardware level resources to ensure application performance and stability. Topics include central processing unit utilization and context switching, system load trends, memory usage including heap and stack behavior, paging and swapping effects, disk input output operations and free space, and network bandwidth utilization and packet loss. Know diagnostic tools and commands for observing these signals, recognize patterns of resource contention and exhaustion such as out of memory and high input output wait, and understand mitigation techniques including tuning, resource limits, throttling, caching, capacity planning, and vertical or horizontal scaling.
Advanced Linux Performance and Services
Advanced administration focused on service lifecycle, process management, and system performance. Topics include deep systemd service management and unit file authoring, dependency ordering and service recovery, process lifecycle and signal handling, cgroups and resource controls, tuning kernel parameters, diagnosing CPU and memory pressure, understanding page cache and swap behavior, out of memory scenarios, I O performance analysis, interpreting load average, and using performance and sampling tools such as top, htop, pidstat, iostat, vmstat, sar, and perf for identifying bottlenecks and implementing mitigations.
Linux Troubleshooting and Diagnostics
In depth troubleshooting and diagnostic techniques for complex Linux issues at the system and kernel level. Includes advanced use of strace, ltrace, perf, ftrace, and reading proc and sys filesystems, root cause analysis of memory leaks and resource exhaustion, diagnosing intermittent failures and I O bottlenecks, log analysis, service debugging, containerized environment troubleshooting, and strategies for progressive isolation, replication, and remediation of production incidents. Senior level expectations include understanding kernel interactions, tracing user space to kernel transitions, and designing observability approaches to prevent recurrence.
Performance Strategy and Resource Efficiency
High level strategy for balancing performance, resource constraints, and cost. Topics include trade off analysis, when to optimize versus accept costs, algorithm and data structure selection under resource constraints, power and energy trade offs, memory and storage budgets, and cost aware performance design. Candidates should discuss prioritization, measurement driven decision making, and resource efficient system design.
Performance Debugging and Latency Investigation
Finding the root cause of latency spikes: checking CPU/memory/disk/network utilization, profiling applications, querying slow logs, and identifying bottlenecks. Understanding the difference between resource exhaustion and an algorithmic problem. Using monitoring and tracing tools to narrow down where time is spent.