A data centre is the secure building where the servers that host your website physically live.
A data centre is a purpose-built facility full of servers, networking equipment and storage, kept running around the clock. When you buy web hosting, your website's files and databases sit on a server inside one of these buildings.
Data centres are designed so that servers stay online even when things go wrong. They have backup power, cooling, multiple internet connections and strict physical security. A good one is far more reliable than a server in an office cupboard.
What's inside a data centre
- Racks of servers: rows of cabinets holding the machines that run websites, email and apps.
- Power systems: mains supply backed by batteries (UPS) and diesel generators, so a power cut doesn't take sites offline.
- Cooling: air conditioning or liquid cooling to stop hardware overheating.
- Network connections: links to several internet carriers, so traffic can reroute if one fails.
- Security: access cards, cameras, guards and sometimes biometric checks.
- Fire suppression: gas-based systems that put out fires without damaging equipment.
Why data centre location matters for your website
Data has to travel from the server to your visitor. The further it goes, the longer it takes. A server close to your audience usually gives a lower TTFB and faster pages.
Location can also matter for legal reasons. Some businesses need customer data stored in a certain country or region to meet privacy rules like GDPR.
If your visitors are spread worldwide, a CDN solves much of the distance problem by serving copies of your files from many locations.
Data centre tiers and reliability
Many data centres are rated using the Uptime Institute's Tier system, from Tier I to Tier IV. Higher tiers have more redundant power and cooling, so maintenance or a single failure doesn't cause downtime. Tier III and above are common for hosting, as they allow parts to be serviced without switching servers off.
Remember that the building is only one part of the picture. Your actual uptime also depends on the server hardware, software, backups and the host's SLA.
Data centres and energy use
Data centres use a lot of electricity, both for servers and cooling. Efficiency is often measured by PUE (power usage effectiveness), where a figure close to 1.0 means almost all the power goes to computing rather than cooling. Some hosts and facilities use renewable energy or offset their usage, which is what green hosting is about.
AblePage backs its hosting with a 99.9% uptime SLA.