Last modified: January 24, 2026

This article is written in: 🇺🇸

Web Server Overview

Backend engineers are responsible for setting up and maintaining servers that host web applications, APIs, and databases. A solid understanding of server management principles is crucial for delivering robust, high-performing, and secure systems.

Client-Server Architecture

Client-server architecture underpins most modern networked systems and the internet. It describes how clients (which request services) interact with servers (which provide these services).

+-----------+            +-----------+
          |  Client 1 |            |  Client 2 |
          +-----+-----+            +-----+-----+
                ^                        ^
                |                        |
                |  Request/Response      |  Request/Response
                |                        |
                v                        ^
          +-----+-----+            +-----+-----+
          |           |            |           |
          |           +------------>           |
          |  Server   <------------+  Server   |
          |           |            |           |
          |           |            |           |
          +-----+-----+            +-----+-----+
                ^                        ^
                |                        |
                v                        ^
          +-----+-----+            +-----+-----+
          |  Client 3 |            |  Client 4 |
          +-----------+            +-----------+

1. Client
2. Sends requests for data or services, typically through protocols like HTTP, FTP, or SMTP.

3. Can be anything from a web browser to a mobile app or IoT device.

4. Server

5. Receives and processes client requests, then returns appropriate responses.

6. Could be a web server, database server, mail server, etc.

7. Communication

8. Relies on a network (often the internet).
9. Common protocols include HTTP for web traffic, FTP for file transfer, and SMTP for email.

Architecture Patterns

• Two-Tier Architecture
• Direct communication between client and server.
• Suitable for simple setups or smaller user bases.

+--------+       +------------------+
  | Client |  <--> |    Server (DB)   |
  +--------+       +------------------+

• Three-Tier Architecture
• Separates presentation (client), application (middle layer), and data (database) layers.
• Helps in organizing complex applications, enhancing security, and scaling individual layers independently.

+--------+       +------------------+       +------------------+
  | Client |  <--> |   App Server     | <-->  |   Database       |
  +--------+       +------------------+       +------------------+

• N-Tier (Multi-Tier) Architecture
• Adds more layers, such as separate microservices, caching servers, or specialized business logic layers.
• Offers enhanced scalability, flexibility, and maintainability.

| Client |
          +---+----+
              |
              v
   +-------------------+        +-------------------+
   |  Web Tier (API)   |  <-->  |  Business Logic   |
   +--------+----------+        +---------+---------+
             |                          |
             v                          v
   +-------------------+       +--------------------+
   |  Caching / Queue  |       |  Database / Storage|
   +-------------------+       +--------------------+

Advantages

• Scalability: Servers can handle many clients concurrently.
• Maintenance: Upgrading back-end services does not disrupt client applications.
• Security: Central control over data and authentication.
• Resource Sharing: Efficient usage of server hardware and software resources.

Disadvantages

• Dependency: Clients rely on server uptime.
• Network Dependency: Requires stable network connections.
• Congestion: High load can overwhelm the server if not scaled properly.

Server Types

Servers can be provisioned in different ways depending on performance requirements, budget, and desired control:

1. Dedicated Servers
2. A single physical machine dedicated to one application or client.

3. High performance, maximum control, but often costlier.

4. Virtual Private Servers (VPS)

5. A virtualized portion of a physical server.

6. More affordable than dedicated servers, offering reasonable performance and control.

7. Cloud Servers

8. Managed by cloud providers like AWS, Azure, or Google Cloud.
9. Highly scalable and flexible, pay-as-you-go model.
10. Cost can vary based on usage and resource consumption.

|  Client 1 |
      +-----+-----+
            |
            | HTTP Request
            v
+-----------------------+
|      Web Server       |
|-----------------------|
| - Hosts Web Pages     |
| - Processes Requests  |
| - Sends Responses     |
+-----------------------+
            ^
            | HTTP Response
            |
      +-----+-----+
      |  Client 2 |
      +-----------+

Operating Systems

• Linux (Ubuntu, CentOS, Debian, etc.)
• Popular in server environments for stability, security, and open-source ecosystem.

• Powerful command-line tools, extensive community support.

• Windows Server

• Chosen for .NET environments or for integrating with other Microsoft services.
• Graphical interfaces and Windows-centric tools.

Server Configuration

To run services effectively, servers require careful setup:

• Web Server Software: Apache, Nginx, IIS, or others.
• Database Servers: MySQL, PostgreSQL, MongoDB, etc.
• Caching Systems: Redis or Memcached for faster data retrieval.
• Language Runtimes/Frameworks: Node.js, Python, Ruby, Java, PHP.

Example Setup (Ubuntu + Nginx + Node.js + MongoDB)

1. Install OS: Start with Ubuntu as the server operating system.
2. Install Nginx: Configure it to serve static files and proxy requests to Node.js.
3. Install Node.js: Run the application logic or API.
4. Install MongoDB: Store and manage application data.
5. Configure Firewalls: Secure traffic, allowing only HTTP/HTTPS and SSH as needed.

Security

Securing a server is crucial to prevent unauthorized access and data breaches:

• Firewalls: Configure iptables or ufw to control network traffic.
• SSL/TLS Certificates: Use HTTPS for secure client-server communication.
• User Access Control: Implement key-based SSH authentication, minimal open ports.
• Regular Updates: Keep system packages and software patched.
• Intrusion Detection: Tools like fail2ban or tripwire to monitor malicious activity.

Performance Tuning

Optimizing server performance involves balancing resource usage and application demands:

• Load Balancing: Use reverse proxies (e.g., HAProxy, Nginx) or load balancers to distribute requests.
• Caching: Implement in-memory caches or content caching to reduce repeated computation.
• Resource Monitoring: Tools like top, htop, or nmon help identify CPU, RAM, or I/O bottlenecks.
• Database Indexing: Proper indexes and query optimization for better query performance.

Backup and Disaster Recovery

A robust strategy ensures minimal downtime and data loss:

• Regular Backups: Automate database snapshots and file backups (daily, weekly).
• Redundancy: Set up replicas or high-availability clusters (e.g., MySQL replication).
• Recovery Testing: Regularly test restoring backups to validate the process.

Automation and CI/CD

Streamlined development and deployment pipelines keep the server environment consistent and reliable:

• Scripting: Use Bash, Python, or Ansible for repetitive admin tasks.
• Continuous Integration: Tools like Jenkins, GitLab CI automate building and testing code changes.
• Continuous Deployment: Deploy updates quickly and safely to staging or production.

Monitoring and Alerts

Detecting and responding to issues quickly is essential:

• Monitoring Tools: Nagios, Prometheus, Grafana for real-time metrics and alerting.
• Log Management: ELK Stack (Elasticsearch, Logstash, Kibana) for centralizing and analyzing logs.
• Alerts: Configure email/SMS/Slack alerts for system anomalies, such as high CPU usage or downtime.