Coping with co-location

Let someone else do the dirty work. Danny Bradbury shows you how a third party can babysit your Web server

Let someone else do the dirty work. Danny Bradbury shows you how a third party can babysit your Web server.

What is co-location?

Co-location involves putting your Web server into a facilities house, where it can be managed by professional staff on a 24-hour basis. In this sense, it differs from straightforward Web hosting, which involves running your software on someone else's server.

Why do it?

One of the biggest problems for companies running e-commerce sites is maintaining the performance of their servers. When IT management isn't your core business, it's easy to make mistakes in this critical area. Co-locating is a good way to free up resources so they can focus more on enhancing the website.

Another advantage to co-locating is that it can increase the data throughput to your site, giving visitors a more enjoyable experience.

When you run your Web server at your own location, you'll have a leased line at best, probably offering no more than 64Kbps, which will restrict customer access.

Where should I co-locate?

Co-locating with a major Internet service provider (ISP) or specialist facilities house usually involves putting your server directly into the Internet exchange, or at least on to a faster link into the exchange, which is where all ISPs share a link to the major Internet backbone. There are two main Internet exchanges in the UK - the London Internet Exchange (LINX) and MANAP, which is based in Manchester. If your server sits within one of these exchanges, you can expect direct access to the backbone, which can run at multiple gigabytes.

Who do I co-locate with?

There are many different companies offering co-location services. For example, visit the LINX site at and look at its member list to find a range of companies that can host your servers.

Redbus is one company offering hosting solutions through its Interhouse division. The company presents itself as an alternative to traditional hosting ISPs, which it says generally run your website on their own servers rather than giving you the opportunity to put your hardware in their site. The company then offers you a chance to select your ISP independently rather than simply using the services of the company that is hosting your website on its own equipment.

How can I evaluate a co-location partner?

When selecting a co-location company, there are certain things to look for. Because hosting is a core competency for the co-location partner, its site should be resilient. Look for a stable, redundant power source, with good uninterruptible power supply backup. An on-site generator is a bonus, because if someone cuts through a power line feeding the company, or a local power station experiences a service disruption, your server can carry on working.

The company's network connections should also be resilient. Multiple connections with access points on different sides of the building are desirable. This way, if an errant workman cuts through the network link on one side of the building accidentally, the facilities house can still access the Internet from the other side.

XTML, for example, which is a Manchester-based application hosting company, maintains a network without a single point of failure. If one part of the network goes down, data can still get to and from the Internet.

Can I be sure they're secure?

Security is a prime concern in any co-location facility. With the increase in hacker attacks on e-commerce sites, physical attacks are also a possibility, and both the physical and logical security of the building should be evaluated.

Some companies go overboard. XTML, for instance, uses a high-security vault in the Bank of England, which it leased and converted to a data centre in February 2000. The vault contains twin steel and concrete reinforced walls, and a 20 ton steel door.

XTML prides itself on being immune to electromagnetic pulses from nuclear devices; although, in the event of a nuclear war, it's unlikely anyone will be buying much online anyway. Nevertheless, this protection makes it impossible for third parties to 'sniff' signals transmitted via electromagnetic radiation.

Can I evaluate my provider on an ongoing basis?

Finally, make sure you have a service level agreement (SLA) to guarantee the resilience of the site. This includes an SLA for backing up data so that if your server experiences a critical failure, you won't lose your customer data.

Ask for your server to be mirrored so that if it stops working, you can carry on serving customers using the other box. This will cost more because the service will be your own, but it's vital to ensure as much uptime as possible.

Critical success factors

  • Choose a reliable service provider with a robust network
  • Pay for a fault-tolerant server to install in its data centre
  • Evaluate the service provider's security arrangements
  • Ensure your server is mirrored and that your data is backed up
  • Ideally, choose an ISP-independent data centre so you can switch ISPs at will

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