Understanding prefabricated modular data centres

It is no secret that prefab data centres offer a number of advantages, when compared to ‘stick built’ data centres, such as speed of deployment, predictability, scalability and life cycle cost. While the benefits of prefab data centres are well documented, there is a lack of common language and classification for prefabricated solutions - this has created confusion.

There are many approaches to implementing prefab modular data centres, so without a standard terminology for describing them, selecting the best type for an organisation becomes difficult. So too does choosing and integrating the most appropriate data centre management software system.

In order to alleviate some of the ambiguity around prefab data centres and ensure that the optimal prefab solution is selected to meet business needs, managers need to gain an understanding of the attributes, limitations and benefits of each form of prefab data centre and the associated data centre management technologies.

What is a prefabricated modular data centre?

In order for data centre managers to understand the many approaches to prefab data centre solutions, they must first understand the different terms for various types of prefab data centres. A prefabricated modular data centre can be described as prefabricated, containerised, modular, skid-based, pod-based, mobile, portable, self-contained, all-in-one and more. However, these terms all refer to the same basic definition that a prefabricated modular data centre is a data centre system or subsystem that is preassembled in a factory.

In simple terms, a prefab data centre is the following:

• Made up of at least one pre-engineered, factory-integrated and pretested assembly of subsystems that have traditionally been installed separately on-site.
• Mounted on a skid or in an enclosure.

The prefabricated modular data centre framework

The most common framework for classifying the various types of prefab data centres is based on three attributes:

• Functional block, which includes power, cooling and IT.
• Form factor, which includes ISO module, enclosure and skid-mounted.
• Configuration - a fully prefabricated data centre, a semi-prefabricated data centre, or an all-in-one data centre.

In the first instance, prefab data centres are distinguished by functional blocks primarily because some prefab data centres only require a specific resource, such as power or cooling. Different personnel with different skill sets are also needed to operate and maintain each element, for example, facilities staff vs IT staff, and mechanical operators vs electrical operators. The second key attribute, form factor, is distinguishable on application. For example, a prefab data centre may be permanently mobile, ie, on wheels, or it may be constrained by its capacity. The final element, ie configuration, explains how the prefabricated functional blocks are deployed.

When selecting the optimal prefab data centre solution, all three components must be considered as outlined in detail below.

Functional block

The functions of a data centre can be broken down into three major categories - the power plant, the cooling plant and the IT space.

The prefabricated data centre can provide all three functions but in most cases will provide only one, due to data centre requirements. For example, if a data centre has stranded capacity in its facility, which is often the case, a prefabricated module is only needed for a specific resource. This is also the case where greater IT capacity is needed and a single IT space is required, or if IT, mechanical and electrical personnel need to be separated to reduce human error and risks.

• Power - A prefabricated power module is designed to provide power to the data centre. The typical subsystems within a power facility module are switchgear, ATS, UPSs with batteries, transformers and panel boards. Lighting and security may also be integrated within the power module.
• Cooling - Prefabricated data centres use a range of cooling systems to support the IT space, primarily based on cost, efficiency and reliability.
• IT Space - A prefabricated IT space is one that houses the IT equipment and also the support for the infrastructure to distribute power and air to the systems.

Form factor

Prefabricated data centres are known to take on different form factors, or types of structures, size and shapes. The form of a particular prefab data centre solution impacts its flexibility, whether it can be transported or moved, its location (inside or outside) and its placement, for example, whether it is inside or on a rooftop. There are three general forms of prefabricated data centre modules including ISO module, enclosure and skid-mounted.

ISO Module - ISO modules are standardised re-usable steel shipping enclosures, designed for safe, efficient and secure storage and movement of materials from one type of transportation to another. Often, this form factor also requires lighting and security as they are used for operation and maintenance.

Enclosure - Enclosures are less standard in terms of dimensions and do not necessarily meet specific shipping standards like ISO modules. Enclosures can also be referred to as shells, metal houses and pods. Enclosures are flexible in terms of the IT and layout of equipment.

Skid-mounted - A skid-mount is a method of distributing and storing machinery where the machinery is permanently mounted in a frame or onto rails or a metal pallet. The equipment can then be easily and securely transported and used as a full unit.

The form factor or combination of form factors which is best for any given prefab data centre is based on what is needed from the data centre manager, such as whether it needs to be transported, whether it has stranded capacity and its scalability.

Configuration

There are many different ways functional blocks can be implemented in a prefab data centre and the approaches fall under three main categories: semi-prefabricated, full prefabricated and all-in-one.

A semi-prefabricated data centre is made up of a combination of prefabricated functional blocks and traditional ‘stick-built’ systems. Semi-prefabricated data centres are most commonly implemented when an existing data centre is out of bulk power, cooling or IT space or if space is already constrained.

A fully prefabricated data centre is made up of completely prefabricated IT, power and cooling modules and is typically implemented when the scale of the data centre is vital to the success of the project.

An all-in-one data centre is a self-contained, single-enclosure data centre with IT, power and cooling systems and is most often mobile and therefore most commonly used when movability and location are key.

Integrating DCIM with prefabricated models

To consider prefabricated data centre models also means the managers must rethink the way management systems are written for prefabricated modules, whether they include IT, or simply power or cooling.

Data centre infrastructure management (DCIM) software provides a complete picture of the health of a data centre and is designed to identify and resolve data centre issues. It increases understanding of capacity and utilisation in the environment through monitoring and controlling data centre physical infrastructure (DCPI) in real time and based on changing loads. DCIM can also help identify unused or stranded capacity by coordinating assets more efficiently and conducting predictive analysis of what will happen to the physical infrastructure before loads are moved.

However, as prefabrication simplifies physical infrastructure, when a prefab data centre model is used in conjunction with DCIM, the DCIM software is best utilised as a ‘plug and play’ in order to make its integration as simple as possible. This means that any data centre management system or software should automatically subscribe to the key data from any new module and populate this to the DCIM application without a lot of custom engineering, design or programming input.

When considering prefabricated data centre solutions, data centre managers should also be looking for management systems that can be absorbed and integrated into DCIM seamlessly, and deliver data automatically such as Schneider Electric’s StruxureWare software.

Selecting the best data centre solution

There are many approaches to implementing prefabricated modular data centres; however, a lack of common terminology for describing and explaining them has led to confusion across the industry and hesitation from data centre managers in selecting the best solution for their organisation.

The optimal approach to prefabricated data centres, including the most appropriate configuration, functional blocks and form factors, will depend on the specific business need of the operation. However, understanding the terminology and benefits of each type will help the data centre manager to classify and analyse the available solutions and, ultimately, select the most appropriate form.

When considering prefabricated data centre solutions, the data centre manager must also consider the approach to data centre management and software, and how DCIM solutions will be best integrated with the data centre system in order to achieve optimal results throughout the project.