Half-Rack Colocation Explained: What You Get, and When It Beats a Full Rack

Colocation (“colo”) is simple in principle: you own the hardware, the datacenter provides the building around it — power, cooling, physical security, and a fast, redundant network. The only real question most growing teams get stuck on is how much space to rent. A single unit feels too small, a full rack feels like a big jump. A half rack is the answer in between, and for a lot of businesses it’s the most economical place to land. Here’s exactly what it includes and when it’s the right call.

What is half-rack colocation, exactly?

A standard server rack is measured in “U” (rack units) — a full rack is commonly 42U to 48U tall. A half rack gives you roughly half of that space — typically in the region of 20U to 24U (confirm the exact figure for your datacenter’s racks) — usually as a lockable section of a shared rack, or your own dedicated half-height cabinet.

Crucially, it’s not just empty space. A proper half-rack package comes with its own allocated power circuit, a share of the datacenter’s cooling, a network uplink, and the physical security and monitoring that protect everything in the facility. You bring the servers; the datacenter guarantees the environment they run in.

What’s included in a half rack

The details vary by provider, but a well-specified half rack should cover all of the following. It’s worth checking each one before you sign:

Space: your allocated U’s in a lockable rack or cabinet, so only your team touches your hardware.

Power: one or more dedicated circuits with a stated amperage, ideally with redundant (A+B) feeds so a single power path failing doesn’t take you down.

Cooling: datacenter climate control sized to your rack’s heat load — not something you have to plan for yourself.

Network: a committed uplink (for example 1 Gbps — confirm the figure and any bandwidth allowance), one or more IP addresses, and redundant routing to the wider internet.

Remote hands: datacenter staff who can physically reboot, re-cable or swap a drive for you when you can’t be on-site — essential if the facility isn’t next door.

Security & access: 24/7 physical security, access control, and a clear process for when your team needs to visit.

The scenario: outgrowing your servers

Half rack vs full rack: which do you need?

The honest answer is usually “whichever one you’ll actually fill within a year or two.” Here’s how they compare:

Pick the half rack if you’d be paying for a full one that sits mostly empty. Step up to a full rack when you’re consistently past the halfway mark.

When a half rack is the right choice

A half rack tends to be the smart pick when you have a handful of physical servers plus networking gear that you want in one managed, secure place; when you’ve outgrown scattered VPS or single dedicated boxes but a full rack would sit half-empty; when you want datacenter-grade power, cooling and connectivity without running your own server room; and when predictable monthly cost matters more than maximum headroom. If you’re only running one or two machines, colocation of a few units may be enough. If you’re scaling fast or packing dense hardware, look straight at a full rack.

Why the datacenter behind the rack matters

Colocation is only as good as the facility around your hardware. Two things decide that: where the datacenter physically sits and how it’s run. A datacenter in the EU keeps your data under European jurisdiction — which matters for GDPR and for European users’ latency. And an operator that owns and runs its own facility, rather than reselling space in someone else’s, gives you a single accountable point for power, network and remote hands.

hosting662 runs its own datacenter in Europe, with redundant power and network, a fast uplink and hands-on staff on site. If you’re weighing a half rack, that combination — EU location plus a single operator who owns the stack — is what keeps colocation simple as you grow. You can see the options on the rack hosting page, and if you’re still deciding between colocation and virtual servers, our European VPS guide is a good next read.

Frequently asked questions

What is half-rack colocation?

Half-rack colocation is renting about half of a standard server rack in a datacenter — typically around 20 to 24U of lockable space — with its own allocated power, cooling and network uplink. You install and own the servers; the datacenter provides the secure, powered, connected environment they run in.

How many servers fit in a half rack?

It depends on the size of each server, but a half rack of roughly 20 to 24U comfortably holds several 1U or 2U servers plus a switch and a firewall — often four to ten machines with room for networking gear. Denser or larger chassis will use the space faster.

Is a half rack cheaper than a full rack?

Yes. You pay for about half the space, power and cooling, so the monthly cost is lower. It’s the more economical choice whenever a full rack would sit mostly empty — you get datacenter-grade infrastructure without paying for capacity you won’t use for a year or two.

What’s the difference between colocation and a VPS?

With colocation you own the physical hardware and the datacenter houses it. With a VPS, the provider owns the hardware and rents you a virtual slice of it. Colocation gives you full control and is cost-effective at scale; a VPS is simpler and cheaper when you don’t want to buy or manage physical servers.

Do I need to visit the datacenter to manage my servers?

Rarely. Most day-to-day management is done remotely, and datacenter “remote hands” staff can physically reboot, re-cable or swap parts on request. You’d typically only visit for the initial install or a hardware upgrade — useful to know if the facility isn’t nearby.

The bottom line

Half-rack colocation is the practical middle ground for a growing estate: enough space and power for a handful of servers and your networking gear, in a secure EU datacenter, without paying for a full rack you’d leave half-empty. Get the power, cooling, uplink and remote-hands details in writing, check the rack size and jurisdiction, and it’s one of the most cost-effective ways to run your own hardware.

If you’re at that stage, take a look at hosting662’s rack hosting — a half rack in our own European datacenter, with the infrastructure and staff already in place.