How to Determine Your Colocation Space Requirements?

17 Nov 2020 by Colocation

Here is the typical scenario – you are thinking about a hardware refresh or a new purchase of physical servers, storage devices and networking gear for your IT workloads. You consider an offsite colocation data center facility as one option and on-premise hosting as another. You are leaning towards colocation because it provides better power, connectivity and redundancy than hosting your servers in an internal data center or telco closet. The question becomes – how much colocation space do you need?

When it comes to server colocation, there are a number of different space configurations and service options available. It is important to note that not all colocation providers offer the same space, services or pricing options. Most colocation providers require a minimum of a colocation cabinet or full rack while smaller providers offer colocation for a single server. Yet, other colocation data center providers base the amount of colocation space you need on your total power requirements.

In this article, I will review the different colocation space configuration options offered by both retail and wholesale colocation providers. I will also look at examples of the most common colocation space and power configurations. Last but not least, I will quickly touch on colocation pricing and how that figures into your colocation data center space requirements.

Let’s get started.

Colocation Per Unit (U), Single Server, Rack Unit

The smallest amount of data center colocation space that you can lease is measured in per unit (U). This type of colocation is sometimes referred to as shared colocation because it is a shared rack with multiple tenants sharing space, power and bandwidth. It is also referred to as single server or rack unit colocation.

Examples of per U colocation include 1U, 2U, 3U or 4U colocation space. A full colocation rack can accommodate 42U or more of colocation space. What is the size of 1U colocation? 1U colocation is equal to approximately 19” wide by 36” deep and 1.75” tall. It can vary by provider and country; however, these dimensions are the most common.

How much does 1U colocation cost? Pricing for 1U colocation varies based on factors such as power, bandwidth, geographic location or market, provider, data center facility, and add-on services. You can expect to pay anywhere from $49 to $99 per U per month. It may or may not include cross-connects.

Per U colocation is great for small businesses, startups, and individuals such as gamers that want to host their own dedicated server in a data center. This type of colocation provides superior results over hosting a server at home or in an office where power, connectivity, bandwidth and latency can impact performance.

It’s important to note that not all colocation data center providers offer colocation space in 1U increments. Many require a minimum of a full rack or locking cabinet.

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(1/4) Quarter Rack Colocation

Quarter rack colocation is a popular option for small and medium-sized businesses. How much colocation space is included in a quarter rack? A quarter rack is about 10U of total colocation space with 8U to 9U of usable space. The number of rack units (U) in a quarter rack is determined by the size of the rack enclosure which can be 42U, 46U, 47U, and 48U. It is also determined by the spacing of the divider shelves.

How much does quarter rack colocation cost? Typically, you can get a quarter rack of colocation space in a quality data center for $299 to $499 per month. This often includes space, power, bandwidth, remote hands, and IP addresses. It may or may not include cross-connects.

(1/2) Half Rack Colocation

Half rack colocation space is great for small and medium-sized businesses and startups. How much space do you get with a half rack? A half rack of colocation provides approximately 20U of total colocation space with 16U to 18U of usable colocation space. As always, this depends on the size of the rack enclosure selected by the colocation data center provider.

What does a half-rack cost? You can expect to pay anywhere from $499-$699 per month for a half rack of colocation space. This typically includes the space, power, connectivity, IP addresses, cross-connects, remote hands and monitoring.

Full Rack Colocation and Locking Cabinets

Full rack colocation and locking cabinets are the most common colocation space offerings among nearly all colocation data center providers. It is used by business and enterprise customers of all sizes and for varying reasons. Full rack colocation can be used to host anything from SD-WAN hardware and VoIP equipment to private cloud servers, GPUs for artificial intelligence (Ai), and backup storage devices for disaster recovery and business continuity.

How much space is included with a full rack? Full rack colocation typically offers 42U of total colocation space with 38U to 40U of usable space. There are certain colocation providers in the United States and Internationally that offer tall colocation cabinets that can house 46U, 47U and 48U.

How much does a full rack or locking cabinet cost? Pricing for a full rack starts around $499 per month with minimal power and basic internet connectivity. Higher-end full rack colocation cabinets can be $2,000 or more. This is highly dependent on the colocation provider, data center facility, location of the data center, and connectivity bandwidth

As mentioned, most providers offer full rack, locking cabinets within their colocation data centers. Each customer is given a combination lock or biometric lock to access their cabinet. Locking cabinets are accessible from the front and back of the cabinet. An electrical outlet is located at the bottom of the cabinet and customers typically provide their own power distribution unit (PDU) to power their servers, storage devices, and networking hardware.

With full rack colocation, you do not have to worry about the per U configuration constraints and configure your rack with spacing in between servers for better airflow.

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Private Cage Colocation

Private cage colocation space is often purchased by large business and enterprise customers. Unlike per U, full racks and locking cabinets, a private cage is considered wholesale colocation space versus retail colocation. There are usually price breaks for wholesale colocation which is based on the customer’s power and space requirements.

How much space is included in a private cage? The minimum for cage space is 50 to 100 square feet. However, common configurations include 10’x10’, 10’x15’, 20’x20’, 50’x50’ cages. The amount of space is determined by the number of servers, storage devices and networking gear and their associated power requirements.

Example of Customer Private Cage Space

For example, a customer may request enough colocation space for 200 blade servers with an average power draw of 200 watts (W). This would equal 40,000W of the total power required or 400 kilowatts (kW). Wholesale colocation is anything between 250kW to 500kW and above depending on the colocation provider.

A full rack typically offers 42U of total space, 38U of usable colocation space, 5kW of total power and 4kW of usable power. With colocation, you can only use 80% of the total allocated power. That is where we get the 4kW of power from.

Knowing this, you would need six full racks of colocation space to house 200 blade servers. That is the colocation space requirement only. And based on your power requirements of 200W per server, you can only place 20 blade servers in each full rack (200Wx20=4kW). In this case, you now need 10 full racks based on your power requirements. This is due to the rack power density constraints of the data center. You could go with high-density colocation which allows higher power density per rack.

It is important to note that metered and unmetered power can be delivered to a private cage space. With metered power, you pay for what you use on a monthly basis. With unmetered, you simply pay a monthly flat-fee for data center power delivered to your private cage.

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Private Suite Colocation Space

Private suite colocation is similar to private cage space with one major difference. A private suite has four hardened walls and a secure door entry. You can think of a private suite as a suite within an office building. It could be a separate floor or suite within a colocation data center.

Private suites range in size from a few thousand to hundreds of thousands of square feet with multiple floors. Private suites are typically marketed towards enterprise customers, web hosting providers, cloud public and private providers, and telecommunications carriers.

Colocation private suite pricing is determined by the availability of space and power within the data center. It is charged at the wholesale rate and contracts for this type of colocation space are multi-year contracts at a minimum. Prices are typically charged per the kWh cost plus the provider markup which covers data center infrastructure buildout costs. This can include both metered and unmetered power.

With private suite colocation, it is more like a commercial real estate transaction than a hosting purchase. There is more to the contracts, terms and the timelines for delivery are often longer due to the buildout of the space which is configured for the customer use case.

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Need Help With Your Colocation Space and Power Requirements? is the #1 data center directory, marketplace and technology platform for IT buyers and sellers for colocation, cloud services and connectivity. As a Enterprise Account Manager, I can help by directly connecting you with the right colocation providers that match your specific location, data center, support, and pricing requirements. We work with all major colocation data center providers including Equinix, Digital Realty, CoreSite, Flexential, Cyxtera, and many more.

Contact Us to learn more about planning and designing your colocation environment. We also provide access to internet, network, cloud direct connect, managed services and cloud infrastructure.

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