What is a blade server?

Like all kinds of servers, blade servers’ fundamental purpose is to provide services to other programs and users in what has become known as ‘the client/server model,’ an architecture that is the bedrock of most modern IT environments.

Blade servers are fundamental components of many data centers, which are physical spaces that house IT infrastructure and enable the building and running of applications and services. Blade servers give enterprises a compact, efficient and highly scalable way to maximize resources in a high-density compute environment where power and physical space are priorities.

Blade servers are widely used, the global blade server market being valued at USD 19 billion last year. It is expected to grow to USD 31 billion over the next 5 years, a compound annual growth rate (CAGR) of 9.1%.¹ Blade servers and other types of server technology are manufactured and sold by some of the biggest IT companies in the world, including Dell, Cisco, Hewlett Packard Enterprises (HPE) and Lenovo.

Blade servers are known as modular server systems, meaning that they are made up of smaller components contained within a small blade enclosure, or server chassis. Here’s a closer look at the core components of blade servers and how they function together in a blade server system.

• Chassis: A compact, box-like structure that contains several thin electronic circuit boards known as server blades.
• Backplane: A circuit board that serves as a single connection point for all the various server blades on a blade server.
• Server blades: Small, modular units that contain a single server along with the computer systems, processors, memory and adapters needed to move data around a network.
• Servers: The individual blades of a blade server contain servers that are dedicated to a specific application, as well as the memory and processors needed to run the application.
• Racks: Racks are units in a server room where many individual blade servers are stored.

Blade servers are categorized according to three aspects of their functionality: performance, storage and connection type:

• Performance: Performance, also known as central processing unit (CPU) performance, is a critical aspect of blade server functionality. Depending on the use case and compute environment, blade servers can be equipped with different CPUs (for example, Intel, Advanced Micro Devices (AMD), Sun Microsystems, or others). The more powerful the CPU, the more functions the blade server can perform. Blade servers with more powerful CPUs are typically reserved for resource-intensive environments like cloud computing and virtualization.
• Storage: Another aspect of blade servers that shapes how they are categorized is their storage capacity, also known as their memory. Blade servers leverage a wide range of common storage systems, such as static RAM (SRAM) and dynamic RAM (DRAM). Blade servers also use more specialized storage architectures, such as double data rate static RAM (DDR SDRAM), for real-time processing.
• Connection type: Blade servers have a uniform design that allows them to be easily moved between data centers and configured to serve various business needs. Some blade servers have a basic ethernet output, while others use Serial Advanced Technology Attachment (SATA) or a Storage Area Network (SAN) for high-speed, high-performance data transfer. Blade servers can be designed to connect with various modern or legacy network environments, depending on resources and needs.

In addition to blade servers, modern data centers primarily rely on two other types of servers: rack-mounted servers and tower servers. While similar to blade servers in their functionality, these two other types have some differences worth noting.

Rack-mounted servers

Rack-mounted servers are a cheaper, slightly smaller option to blade servers, and they are not as high-performing. Also, unlike blade servers, they can’t be ‘hot-swapped’—quickly replaced or repaired without disrupting overall system functionality—making them more difficult to maintain.

Some enterprises still prefer rack-mounted servers because of their cost, compatibility with existing data center technologies and the fact that they can be used as stand-alone servers, providing their resources without a central, unified management. Blade servers, in contrast, can often be used only as part of a larger network.

Tower servers

Tower servers are PCs that have been configured to run like a server. As a desktop computer, they are larger than blade or rack-mounted servers. Tower servers are typically used when an IT administrator needs a dedicated server to provide a specific service or capability. For example, tower servers often enable dynamic host protocol (DHCP) or domain system (DNS) services, giving network administrators more flexibility and control over a network.

Blade server design prioritizes user control and management in the way data is transferred between devices on a network. This architecture yields many benefits that are priorities for enterprise IT administrators, such as energy consumption, cost reduction, flexibility and more.

Blade servers are considered highly flexible solutions, often deployed in tandem with other server systems in a data center or network, enabling system administrators to balance workloads across many servers and devices.

Also, blade servers’ design allows organizations to add or subtract them easily as compute needs change. Blade servers are also hot-swappable, which means they can be easily swapped out without affecting overall system performance.

Blade server design allows for minimal cabling, the use of physical wiring in a data center or network environment to optimize communications between various devices. The number of components they rely on for functionality is simple and minimal as well, and their modular design allows them to be easily stored.

Blade servers typically reduce power consumption in networks and data centers by sharing costly resources, such as power supplies and cooling systems.

Many of the networks and data centers that blade servers enable require high availability, a system’s capacity to run at as near to 100% of the time as possible. To this end, blade servers often include features like redundant power supply, easily swappable components and cluster configurations that enhance availability.

Unlike other kinds of servers, blade servers are ultrathin and composed of the smallest number of components needed for functionality. Each blade, for example, contains all the necessary processors and memory for an individual application to run.

In addition to their size, blade servers’ modular design allows them to be easily stacked with other kinds of servers in a data center or network environment.  

Because of their adaptability and performance, blade servers have become an essential part of supporting the data center and networking needs for many mission-critical applications.

For example, blade servers support the processing and analyzing needs of many big data analytics applications, including many edge computing and Internet of Things (IoT) use cases, where data must be processed in real-time, close to where it is generated.

Because of their modular design, blade servers can be easily added or subtracted from existing IT infrastructure. As compute needs change, blade servers can be scaled up or down.

When virtualized, blade servers are even more scalable, offering IT administrators even more flexibility in customizing their server environment.

Blade servers’ scalability, flexibility and compact form factor make them ideal for a wide range of business purposes. From cloud computing and virtualization to edge computing and Internet of Things (IoT) solutions, here are some of their most popular use cases:

• Data centers: Blade server design makes them a popular choice for many kinds of data centers, including enterprise, cloud and more. Blade servers’ slim, compact architecture allows them to be easily stored in a small physical space, and their ability to share resources helps keep down costs.
• Virtualization: Blade servers are well equipped to host virtual machines (VMs), virtual instances of computers that rely on software instead of hardware to run programs, helping companies consolidate the number of servers they use. With multiple server nodes on a single blade, or chassis, they can maximize compute power in a small physical space.
• Cloud computing: Blade servers are considered strong choices for public and private cloud computing environments due to their scalability and efficiency. Cloud providers often need to maximize compute power in a small physical space and blade servers can pack a considerable amount of computing power into their compact design.
• Internet of Things and edge computing: Blade servers are often deployed at the edges of networks for their real-time processing capabilities. In an edge computing environment, a blade server can analyze and process data close to an Internet of Things (IoT) device, like a windmill or hydroelectric dam. This allows IoT capabilities to flourish and reduces latency, the measurement of delays in a system.

While blade servers are popular in many enterprise IT environments, other kinds of servers have emerged recently that are better fits for more specialized use cases.

Like blade servers, brick servers are designed for high-density compute environments where size and efficiency are imperatives. However, while blade servers require specialized chassis that store individual blades, brick servers are entirely self-contained and can be easily stacked on more standard kinds of server racks.

Brick servers are more compact and adaptable than blade servers. They are also more compatible with other kinds of software and hardware, but they don’t share resources as well as blade servers do.

Enterprises often turn to brick servers in instances where they need to run applications that demand even more compute power per square inch of physical space than blade servers can offer.

Cartridge servers, also known as microservers, are even more compact than blade servers and brick servers. In fact, their name comes from their similarity in size and shape to a printer cartridge.

Cartridge servers offer many of the same benefits as blade and brick servers—size, efficiency, scalability—but on an even smaller scale. Cartridge servers are reserved for highly specialized compute environments like certain kinds of web serving, hosting, video transcoding, big data analytics and more.

Hybrid servers are servers that are a combination of virtualized and on-premises server resources. This architecture allows enterprises to leverage server resources in the cloud on an as-needed basis, while still retaining the resources of on-premises servers.

Typically, enterprises seeking a high level of control and management of their server environment rely on blade servers. However, businesses who want to prioritize the scalability and flexibility of the cloud usually turn to a hybrid server solution.