Server types: what are they?

After answering the question "what is a server?", let's dive deeper into the topic and systematically explore everything related to it. First and foremost, we need to understand server classification—that is, answer the question: what do servers look like and what types exist? After that, we'll be able to learn what servers are used for and how they work.

Servers differ by form factor, management level, resource utilization, purpose, and performance. Let's examine the main types.

Classification by Form Factor

Rack Servers (1U and above)

Flat metal boxes that slide into server racks. Size is measured in units (U)—1U equals 4.45 cm in height. A standard rack can hold up to 42U of equipment.

Characteristics:

Specifications depend on the specific model:

• 1U servers: typically 1-2 processors, limited number of drive bays
• 2U and 4U: more space for expansion, additional drives, and improved cooling

Pros: Compactness, high mounting density, convenient component replacement, expansion flexibility.

Cons: High noise levels, require powerful cooling and dedicated server rooms.

Applications: Data centers, hosting providers, large companies with server facilities.

Blade Servers

Compact modular servers that slide into a shared chassis (enclosure) like blades in a knife handle—hence the name. The chassis provides power, cooling, and network connections for all modules. One chassis can accommodate 8-16 servers.

Pros: Space and power consumption savings, centralized management, high computing density.

Cons: High chassis cost, dependency on it (if it fails, all servers stop), limitations on individual upgrades.

Applications: Large enterprises, banks, telecom operators requiring high computing density. High return-on-investment threshold.

Tower Servers

Standalone servers in a case resembling a regular desktop PC. Operate relatively quietly and don't require special installation locations.

Pros: Simple installation and maintenance, quiet operation compared to rack servers, configuration flexibility, affordable cost.

Cons: Take up significant space when scaling, limited expansion compared to rack servers.

Applications: Small and medium businesses, company branches when only one or two servers are needed.

Classification by Processor Architecture

x86 Servers (Intel/AMD)

Servers equipped with x86 processors. Traditional architecture with high per-core performance. Wide compatibility with enterprise software.

ARM Servers

Equipped with energy-efficient ARM architecture processors.

Pros: Low power consumption, high computing density, affordable cost.

Cons: Limited software compatibility, lower performance for high-core-load tasks.

Applications: Cloud computing, edge computing, web servers, and microservices.

Classification by Management Level

Managed Servers

The provider handles complete support: configuration, monitoring, backups, updates, 24/7 technical support.

Pros: No need for in-house IT specialists, professional support, quick assistance with problems.

Cons: Additional 20-45% on top of server rental cost, limited system control.

Applications: Companies without IT departments, startups, businesses where IT specialists aren't needed daily.

Unmanaged Servers

Client receives a server without pre-installed software and is independently responsible for configuration, security, and maintenance.

Pros: Complete system control, low cost, flexible configuration.

Cons: Requires highly qualified personnel, client bears responsibility for failures.

Applications: Companies with in-house or outsourced system administrators.

Classification by Resource Utilization Method and Server Architecture

Dedicated Servers (Bare Metal)

Physical server entirely at the client's disposal. No one else claims processor time, memory, or disks.

Pros: Maximum and predictable performance, complete isolation, direct resource access.

Cons: Fixed cost regardless of utilization, limited scaling flexibility.

Applications: Mission-critical and resource-intensive applications, high-load databases (Oracle, PostgreSQL) where stable performance is essential.

Cost is higher than VPS, but you get complete resource control.

Virtual Private Servers (VPS)

Virtual machines on a physical server with isolated resources. One physical server is shared among multiple clients.

Pros: Quick deployment, flexible configuration, affordable cost.

Cons: Limited resources, risk of "noisy neighbors"—dependency on other users on the same physical server.

Applications: Startups, web hosting, small to medium-scale corporate projects.

Affordable alternative to dedicated servers.

Cloud Servers

Virtual servers in distributed infrastructure with dynamic resource scaling.

Pros: Instant scaling, pay only for usage, high fault tolerance.

Cons: Dependency on internet connection, potential security risks, resource pricing higher than traditional VPS.

Applications: Projects with variable loads, global applications, rapidly growing startups.

Classification by Purpose and Functional Role

This classification depends on the combination of hardware platform and software. It's important to remember that specialized software often requires specific system resources.

File Servers — Centralized storage and organization of network file access.

Web Servers — Processing HTTP/HTTPS requests and delivering web content to users. Foundation of any website or web application (Apache, Nginx, IIS).

Database Servers — Storage, processing, and management of structured data. The heart of most corporate systems (MySQL, PostgreSQL, Oracle, Microsoft SQL Server).

GPU Servers — Specialized computing systems with powerful graphics processors for machine learning, 3D rendering, and scientific calculations.

Game Servers — Provide multiplayer gameplay with minimal latency and high synchronization.

Mail Servers — Corporate email management, including receiving, sending, filtering, and archiving messages (Microsoft Exchange, Postfix).

Proxy Servers — Intermediaries between clients and other servers, providing caching, filtering, and anonymity.

Load Balancers — Distribute incoming requests among multiple servers to ensure fault tolerance and performance.

Geographic Load Balancers — Direct users to nearest servers based on their geographic location, minimizing latency.

Remote Desktop Servers (RDS) — Provide remote access to work environments and applications, enabling work from anywhere in the world.

Classification by Performance

Entry-Level — 4-8 processor cores, 8-32 GB RAM, HDD/SSD: Suitable for small businesses, simple websites, small office tasks. Affordable solutions for startups and test projects.

Mid-Range — 10-24 processor cores, 64-512 GB RAM, SSD/NVMe: Serve corporate systems for 500-1000 users, medium-volume databases, virtualization. Optimal price-performance ratio for most business tasks.

High-End — 28-32+ processor cores, 1-8 TB RAM, NVMe arrays: Mission-critical systems, big data, scientific and engineering calculations. Premium-class equipment typically rented for specific tasks.

Emerging Technologies

Edge Servers — Placing computing resources close to users. Critical for IoT and autonomous vehicles.

Hyperconverged Infrastructure (HCI) — Integration of computing, storage, and networking in a single unit. Simplifies management but costs more than traditional infrastructure.

Container Platforms — Servers running Docker/Kubernetes for rapid application deployment.

Conclusion

Different classifications serve to systematize and provide detailed descriptions of specific server aspects. Rack servers dominate data centers thanks to high mounting density. Blade servers provide maximum concentration of computing power. Tower servers suit small deployments. VPS and cloud servers offer flexibility and scalability, while dedicated servers guarantee maximum performance and resource isolation. Understanding the differences between server types helps choose the optimal solution for specific tasks and budgets.