Server storage types: a comprehensive guide

Server storage is one of the key components of any IT infrastructure. The selected type of storage or dedicated storage server directly affects application performance, service stability, scalability capabilities, and the overall total cost of ownership of the infrastructure.

Modern server environments use different approaches to data storage, including local disks, network file storage, high-performance SAN systems, and scalable object storage platforms. Each of these types addresses specific tasks and has its own limitations, which must be taken into account when designing infrastructure for particular business workloads.

What Is Server Storage

Server storage is a subsystem of IT infrastructure designed to store, process, and provide access to data for servers, applications, and services. Unlike user-level or local storage, server storage is designed with high workloads, continuous operation, fault tolerance, and scalability in mind.

The primary purpose of server storage is to ensure stable and predictable access to data under all usage scenarios. This includes databases, virtual machines, containerized environments, file services, backup systems, and analytics platforms. Depending on the architecture, storage can be integrated directly into a server, deployed as a separate network device, or implemented as a distributed system.

When selecting server storage, several key factors are considered:

• type of data
• read and write performance requirements
• acceptable latency
• storage capacity
• workload growth over time
• fault tolerance requirements

As a result, server storage is not just a set of disks but a full-fledged infrastructure component that determines the efficiency of the entire IT system.

Main Types of Server Storage

Several fundamental types of storage are used in server infrastructures. They differ in architecture, connection methods, performance levels, and usage scenarios.

• Direct Attached Storage (DAS). Direct Attached Storage refers to storage that is physically connected to a specific server. This may include internal drives or external disk arrays connected directly without using a network.
• Network Attached Storage (NAS). Network Attached Storage is a specialized device or server that provides file-level access over a network. NAS is used for centralized file storage and shared data access.
• Storage Area Network (SAN). A Storage Area Network is a dedicated network designed for data transfer between servers and storage systems. SAN provides block-level access to data with high performance and minimal latency.
• Object Storage. Object Storage uses a different approach to data storage. Information is stored as objects with unique identifiers and metadata, and access is provided via APIs.

Direct Attached Storage (DAS)

Direct Attached Storage is storage that is directly connected to a server without using network infrastructure. Disks or disk arrays are located inside the server or connected through storage controllers. Data access is available exclusively to the server to which the storage is physically attached. This architecture provides minimal latency and highly predictable performance, as there are no network intermediaries involved.

Advantages of DAS

The main advantages of Direct Attached Storage include:

• low data access latency
• high performance for local workloads
• simple setup and maintenance
• no dependency on network infrastructure

Limitations of DAS

Despite its simplicity, DAS has several limitations:

• no shared access for multiple servers
• limited scalability
• challenges in building fault-tolerant clusters
• tight coupling of storage to a specific server

Typical Use Cases

DAS is most commonly used in the following scenarios:

• dedicated servers for specific applications
• databases with high sensitivity to latency
• local virtualization environments
• servers without shared access requirements

Network Attached Storage (NAS)

Network Attached Storage is network-based storage that provides file-level access to data for one or more servers. NAS connects to a local or corporate network and operates as a standalone node optimized for file storage and transfer. Data access is provided via file protocols, allowing NAS to be used as a centralized storage solution for different systems and users.

Advantages of NAS

Key advantages of NAS include:

• shared data access for multiple servers
• easy integration into existing networks
• convenient file resource management
• flexibility when expanding storage capacity

Limitations of NAS

NAS is not suitable for all tasks. The main limitations include:

• performance dependency on network bandwidth
• higher latency compared to local storage
• limitations when working with high-load databases
• performance degradation under a large number of concurrent requests

Typical Use Cases

In practice, NAS is most commonly used for:

• file services and corporate storage
• collaborative document workflows
• backups and archives
• storage of media and user data

Storage Area Network (SAN)

A Storage Area Network is a specialized high-speed network designed for data transfer between servers and storage systems. Unlike NAS, SAN provides block-level access to data, allowing servers to work with storage as if the disks were locally attached.

SAN architectures are typically built on a dedicated network isolated from general corporate traffic, ensuring stable and predictable performance.

Advantages of SAN

The main advantages of SAN include:

• high read and write speeds
• minimal latency
• shared access for multiple servers
• high fault tolerance and redundancy

Limitations of SAN

Despite its efficiency, SAN has several limitations:

• high complexity of deployment and administration
• increased requirements for staff expertise
• higher total cost of ownership
• excessive for small and medium workloads

Typical Use Cases

SAN is most commonly used in the following scenarios:

• virtualization clusters
• mission-critical databases
• high-load enterprise systems
• infrastructures with strict fault tolerance requirements

Object Storage

Object Storage uses a fundamentally different approach to data storage compared to block and file storage. Data is stored as objects, each containing the data itself, metadata, and a unique identifier. Interaction with objects is performed via APIs rather than through a traditional file system. This architecture enables efficient handling of large data volumes and simplifies horizontal scaling.

Advantages of Object Storage

Key advantages of object storage include:

• virtually unlimited scalability
• high fault tolerance through data distribution
• efficient handling of large volumes of unstructured data
• optimization for backups and archives

Limitations of Object Storage

Object Storage is not suitable for all tasks:

• higher latency compared to block storage
• inability to be used directly with traditional file systems
• limited compatibility with some legacy applications
• dependency on APIs and software integration

Typical Use Cases

In practice, Object Storage is most commonly used for:

• backups and long-term data storage
• storage of media files and large datasets
• analytics and archival systems
• geo-distributed infrastructures

Types of Drives in Server Storage Systems

The choice of drive types directly affects the performance, latency, and reliability of server storage. Regardless of the storage architecture, disk characteristics largely determine system behavior under load.

Hard Disk Drives (HDD)

HDDs remain relevant for tasks where storage capacity is a higher priority than data access speed. They rely on mechanical components, which imposes performance limitations.

Key characteristics of HDDs include:

• large capacity at a relatively low cost
• higher latency compared to SSDs
• limited input/output operations per second
• suitable for archives and backup storage

Solid-State Drives (SSD)

SSDs use flash memory and deliver significantly higher performance. In server environments, different types of SSDs are used, varying by interface and performance characteristics.

Key characteristics of SSDs include:

• low latency and high access speed
• high resilience under heavy workloads
• lower capacity compared to HDDs
• higher cost

In server infrastructures, the most commonly used options are:

• SATA SSDs for moderate workloads
• NVMe SSDs for high-performance systems

Impact of Drive Type on Storage

The type of drive determines:

• application and database performance
• virtual machine density
• caching efficiency
• overall system responsiveness

Key Takeaways on Server Storage Selection

The choice of server storage should be based not on universal recommendations but on specific business and technical requirements. The same type of storage can perform exceptionally well in one scenario and be inefficient in another.

There is no universal storage solution. Each approach has its own strengths and limitations. In practice, the most effective infrastructures use a combination of different storage types, distributing workloads according to their characteristics. A well-considered storage selection helps reduce operational risks, avoid bottlenecks, and ensure sustainable long-term growth of IT systems.