What is horizontal scaling?

Add more server instances to distribute incoming load

Upgrade existing hardware with more CPU and RAM resources

Optimize application code to improve per-request efficiency

Migrate local storage to a centralized cloud-based system

What is connection pooling?

Maintain a cache of open database connections for reuse

Create a new database connection for every incoming user

Synchronize multiple database instances for high availability

Encrypt all traffic between the application and database

What is a message queue?

Buffer tasks between services for asynchronous processing

Sort database records based on their arrival timestamp

Manage the priority of incoming HTTP requests at the edge

Verify the identity of users before they access a service

What is rate limiting in production?

Restrict request volume per user to prevent system abuse

Maximize the data throughput of a specific network interface

Calculate the average response time for all API endpoints

Allocate specific CPU time to different background processes

What is the circuit breaker pattern?

Prevent calls to a failing service to allow it to recover

Retry every failed request immediately until it succeeds

Distribute requests across multiple healthy server nodes

Log every service error into a centralized storage system

What is an SLA (Service Level Agreement)?

External contract defining uptime goals like 99.9% availability

Internal metric used by developers to track system performance

Software license agreement governing the use of open-source tools

Security protocol used to authenticate third-party API providers

What is an SLO (Service Level Objective)?

Internal performance target used to guide system reliability

The actual measured availability of a service over 30 days

Legally binding document that specifies financial penalties

Maximum number of concurrent users a single instance supports

What is an error budget?

Calculated allowable downtime used to prioritize new changes

Financial allocation for repairing production infrastructure

Total number of bugs allowed in a release during QA testing

Threshold of failed requests before an alert is triggered

What is incident response?

Structured process for detecting and resolving service outages

Automated scaling of resources during a sudden traffic spike

Customer support workflow for handling user feature requests

The initial planning phase of a software development lifecycle

What is MTTR (Mean Time To Recover)?

Average time required to fix a service after an issue starts

Average time between two consecutive system failure events

Total time spent on developing new reliability features

Minimum time a server can run before a required reboot

What is chaos engineering?

Inject intentional system failures to test resilience

Run production systems without any monitoring or logs

Randomly update dependencies to find potential bugs

Allowing developers to push code without a review process

What is graceful degradation?

Turn off non-core features to keep the primary service live

Permanently remove old features to simplify the codebase

Automatically restart servers when they reach high latency

Reduce the security requirements for internal service traffic

What is bulkhead isolation?

Partition system resources to prevent total failure spread

Replicate data across different physical disk drives

Encrypt data stored at rest to prevent unauthorized access

Use a single large server to handle all service components

What is a canary deployment?

Release new code to a small group of users before everyone

Deploy the new version to all production servers at once

Run the old and new versions in a simulated environment

Switch all traffic from the old cluster to the new cluster

What is structured logging?

Use JSON or key-value pairs to make logs machine-parsable

Write logs in chronological order within a text file

Categorize logs into simple levels like INFO, WARN, and ERROR

Manually review every log entry at the end of the day

What is log aggregation?

Collect logs from multiple sources into a central search tool

Delete old logs automatically to save on storage costs

Convert raw logs into a summarized PDF for management

Compress log files before they are sent to long-term storage

What is distributed tracing?

Track a request as it flows through various microservices

Map the physical location of servers across the globe

Monitor the bandwidth usage of all internal load balancers

Follow the career path of developers across different teams

What is a liveness vs readiness probe (Kubernetes)?

Liveness ensures the app runs; Readiness ensures it can take traffic

Liveness tracks CPU usage; Readiness tracks memory usage

Liveness is for internal users; Readiness is for external users

Liveness measures latency; Readiness measures throughput

What is a load balancer algorithm?

Method like Round-robin used to distribute traffic to nodes

Encryption process that protects data between the LB and user

Decision tree used to determine if a request should be blocked

Compression routine used to shrink the size of HTTP headers

What is a database read replica?

Copy of a database used to handle query traffic and offload primary

Complete backup of the database stored in a different region

Temporary table used to store intermediate calculation results

Write-only instance used to record application audit logs

What is an auto-scaling policy?

Set of rules to add or remove instances based on live metrics

Manual schedule used to reboot servers every weekend

Strategy for increasing the pricing tier of a cloud account

Policy that limits the maximum bandwidth a user can consume

What is backpressure handling?

Signal the data source to slow down when the receiver is full

Increase the frequency of requests to bypass slow network nodes

Switch to a different server when the current one becomes slow

Store all incoming data in a permanent database indefinitely

What impacts cost in scaling?

Usage of compute, data transfer, storage, and redundant nodes

Total number of lines of code written by the engineering team

Frequency of code commits made to the main production branch

Complexity of the CSS used in the frontend user interface

What is blue-green deployment?

Maintain two identical environments and switch traffic between them

Color-code different versions of the API for developer testing

Deploying code updates on Tuesdays and Thursdays only

Splitting the database into two halves based on the user ID

What is a feature flag?

Remote toggle to enable or disable code without a new deploy

Special icon used in the UI to highlight new application updates

Code comment that marks a section for future development

Strict rule that prevents any new features from being added

What is observability vs monitoring?

Monitoring alerts on symptoms; Observability enables deep debugging

Monitoring is for hardware; Observability is for software

Monitoring is automatic; Observability requires manual data entry

Monitoring uses logs; Observability only uses metrics and traces

What is an alerting strategy?

Notify on actionable symptoms instead of noisy low-level events

Send an email to the whole company for every server warning

Only trigger alerts during standard business hours (9am to 5pm)

Log every alert to a local text file without sending notifications

What is eventual consistency?

Distributed data model where replicas will eventually align

Requirement that all database writes must succeed or fail together

System state where data is deleted after it becomes one year old

Configuration that ensures every server has the exact same hardware

What is a cache invalidation strategy?

Logic used to decide when to remove or refresh cached data

Process of adding more RAM to the caching server cluster

Technique for encrypting cache keys to prevent data leakage

Method for ensuring that every user gets a unique cache key

What is security hardening in production?

Apply multiple layers of protection to minimize the attack surface

Physically lock the server racks in a secure data center

Require all developers to change their passwords every 24 hours

Remove all external internet access from the entire company network

Quizzes

Prev in BackendNode.js & Express Fundamentals: Building Server Applications

Backend DevOps

Production Backend: Scaling, Monitoring & Reliability

Mohammad Abu Mattar20 QuestionsIntermediatePublished: 14 Mar, 2026

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Production Backend: Scaling, Monitoring & Reliability

Up to 20 questions, shuffled on every run

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Enterto start

Welcome to the “Production Backend: Scaling, Monitoring & Reliability” quiz! This quiz tests your knowledge of key concepts and best practices for running production backend systems at scale. You’ll be challenged on topics like scaling patterns, monitoring strategies, error handling, resilience techniques, capacity planning, and incident response. Each question includes detailed explanations to help you learn from any mistakes. Good luck!

Answer key and explanations20 questions

The quiz above draws 20 questions at random from these 30, so a second attempt will not be the same run. Everything in the pool is listed here.

What is horizontal scaling?
AnswerAdd more server instances to distribute incoming load
What is connection pooling?
AnswerMaintain a cache of open database connections for reuse
What is a message queue?
AnswerBuffer tasks between services for asynchronous processing
What is rate limiting in production?
AnswerRestrict request volume per user to prevent system abuse
What is the circuit breaker pattern?
AnswerPrevent calls to a failing service to allow it to recover
What is an SLA (Service Level Agreement)?
AnswerExternal contract defining uptime goals like 99.9% availability
What is an SLO (Service Level Objective)?
AnswerInternal performance target used to guide system reliability
What is an error budget?
AnswerCalculated allowable downtime used to prioritize new changes
What is incident response?
AnswerStructured process for detecting and resolving service outages
What is MTTR (Mean Time To Recover)?
AnswerAverage time required to fix a service after an issue starts
What is chaos engineering?
AnswerInject intentional system failures to test resilience
What is graceful degradation?
AnswerTurn off non-core features to keep the primary service live
What is bulkhead isolation?
AnswerPartition system resources to prevent total failure spread
What is a canary deployment?
AnswerRelease new code to a small group of users before everyone
What is structured logging?
AnswerUse JSON or key-value pairs to make logs machine-parsable
What is log aggregation?
AnswerCollect logs from multiple sources into a central search tool
What is distributed tracing?
AnswerTrack a request as it flows through various microservices
What is a liveness vs readiness probe (Kubernetes)?
AnswerLiveness ensures the app runs; Readiness ensures it can take traffic
What is a load balancer algorithm?
AnswerMethod like Round-robin used to distribute traffic to nodes
What is a database read replica?
AnswerCopy of a database used to handle query traffic and offload primary
What is an auto-scaling policy?
AnswerSet of rules to add or remove instances based on live metrics
What is backpressure handling?
AnswerSignal the data source to slow down when the receiver is full
What impacts cost in scaling?
AnswerUsage of compute, data transfer, storage, and redundant nodes
What is blue-green deployment?
AnswerMaintain two identical environments and switch traffic between them
What is a feature flag?
AnswerRemote toggle to enable or disable code without a new deploy
What is observability vs monitoring?
AnswerMonitoring alerts on symptoms; Observability enables deep debugging
What is an alerting strategy?
AnswerNotify on actionable symptoms instead of noisy low-level events
What is eventual consistency?
AnswerDistributed data model where replicas will eventually align
What is a cache invalidation strategy?
AnswerLogic used to decide when to remove or refresh cached data
What is security hardening in production?
AnswerApply multiple layers of protection to minimize the attack surface