Quarter rack in a data centre

Small-scale customers (especially those wanting a quarter rack or half rack rather than a full rack) often find the response from some colocation providers rather limited. But at Colo-X, we’ve a long track record of sourcing high-quality quarter and half racks in key colocation ecosystems and other parts of the market, both within London and throughout the UK.

Finding the best fit between your needs and what is available in the market is one of the key ways we add value, and we’ve extensive experience in sourcing quarter racks and half racks. So if you’ve a colocation need, challenge or question, we’re ready to help. Below, we answer:


What is driving the need for part-rack colocation?

Quarter racks and half racks in a data centreWith the need for interconnection continuing to grow, service providers and direct enterprise customers are all finding the idea of a point of presence in a well-connected data centre increasingly hard resist.

Access to ‘fat pipes’, consistent and low-latency connectivity to upstream providers (either cloud or network) and the reliability of the infrastructure itself for improved availability, are all strong motivators for using third-party colocation data centres.

The challenge for smaller colocation users is that the industry is geared to selling full-height racks. These are usually 42–48U tall, with power in the range of 3.5–4kW, and 16–20Amps per rack. For many users, this is simply far in excess of their needs. (A full rack with 16Amps can cost as much as £1,800 per month in some London colocation ecosystems – a fairly hefty cost for a small user!)

As a result, many buyers are looking for smaller colocation options: typically a secure, dedicated quarter rack or half rack. Some providers (such as partners of the larger operators, or many of the smaller independent data centre operators) are making quarter and half racks available to service this niche.

What are the typical use-cases for a quarter or half rack?

Colo-X specialises in the retail part of the colocation market, so a fair portion of our enquiries are for quarter or half racks. In general, we find there are two types of users:

Small (and even large) service providers often need small points of presence in key colocation ecosystems such as Telehouse Docklands, Interxion, DRT Sovereign House, Equinix’s LD8 (former Telectiy HEX) or the Equinix Slough campus (LD4, 5, 6, 7 and 10).

While the actual physical footprint may be small, it can still represent a crucial piece of network infrastructure for the buyer. And given the cost of operating in ecosystems, a quarter or half rack can represent a substantial cost saving against the cost of a full rack – especially when some operators impose high minimum-power commitments per rack.

Quarter rack cabinet in Equinix LD5, Slough

Quarter rack cabinet in Equinix LD5, Slough

For a small regional ISP, the use case may be to house a router and a switch or two. A MikroTik Cloud Core router is only 1U and a common workhorse for the regional ISP industry. So a pair of them and a pair of switches makes 4U, plus a server or two (for billing, monitoring etc) and a patch panel, and the quarter rack is working pretty well.

For larger networks, this small point of presence is usually where an end-client needs to house a router or firewall to terminate a service from the carrier. For example, we’ve put one large global carrier into Global Switch’s London East data centre so their client could connect directly to Google Cloud. They simply needed to house a router and then run two cross-connects, one to the carrier and a second to Google Cloud.

For large and small companies, a quarter or half rack provides a secure, cost-effective point of presence, while still offering all the benefits of the underlying ecosystem, including the ability to run cross-connects. A quarter rack can often be responsible for up to 10 separate cross-connects, which demonstrates the value these smaller users can bring to a colocation ecosystem.

For users not needing ecosystem access, a sub-rack is simply a reflection of the limited physical space required. The UK market offers a wide range of colocation providers within London and the South East, as well as in the regional market away from London (where there are great quality sites at substantially lower costs than the expensive ecosystems).

Of the 120+ UK data centres in the Colo-X database, we classify 30 as ‘premium’ – meaning they are operated by the large global operators. Most (but, importantly, not all) of these we rate as ‘ecosystems’.

This means about 100 facilities are suitable for users for whom ecosystem access is not a necessity. And even in wholesale-focused data centres, we can often source retail colocation solutions – either rack-by-rack or as part-racks – from managed-service providers taking large-scale suites in these high quality facilities.

A quarter or half rack offers an entry point to third-party data centres at an even lower cost. Lots of the independent providers in this part of the market (many of whom often started out as small-scale data centre users themselves) are very familiar with part-racks, and are great at supporting relatively small-scale customers.

What should you look for in a quarter rack or half rack?

Colocation buyers sometimes fall into trap of thinking that one quarter rack will offer the same features as another. But options vary, so caution and a clear idea of what is a must-have and what is a nice-to-have are necessary. Here’s a rough overview of some of the features we look for or expect:

  • 9-12U of rack space in a quarter rack / 20-24U of rack space in a half rack

  • Dual power bars, A+B

  • 8 x C13 sockets in a quarter rack / 16 x C13 sockets in a half rack

  • Digital power meter (so you can monitor your power usage)