Data centre doesn't like your face? That's a good thing

Your company has decided, quite sensibly, that it wants to move its application infrastructure to a data centre rather than living with the risk of an on-premise approach. So how do you choose the data centre you should move to?

Location

Location is a compromise of locality versus suitability, but in my mind you should lean toward suitability. A “suitable” location is one that's close enough to civilisation for the power supply to be appropriate (more about that in a bit) and for you to be able to get sensibly priced telecoms links from multiple reliable providers.

It needs to be close to decent transport links: even if you're happy for it to be several hundred miles away from home, you still don't want to have to hitch a ride on a farm cart to get there from the nearest station. I'm also averse to data centres bang in the middle of busy cities.

This is partly because they're too susceptible to the modern-day penchant for civil engineering: JCBs have a similar attraction to data and power cables as moths have to light bulbs.

Additionally, though, if the data centre is in a city then it's likely to be just one or two floors in a shared building, with the obvious hazard of third-party-induced disaster such as fire or flood, instead of a custom-made, dedicated facility.

While it's useful for the data centre to be close to your organisation's premises, it's not an absolute necessity so long as you provide yourself with all the tools for remote infrastructure management. Happily, there's a whole feature in this series dedicated to explaining how you can do that.

What tier?

Data centres are classified in “tiers”, which describe the level of resilience you can expect from each location.

The tiers are numbered from one to four (higher is better): so while a Tier-1 data centre has single points of failure and an availability level that expects downtime of up to about a day a year, at the other end of the scale a Tier-4 data centre has multiple fault tolerance and an expected downtime of no more than about half an hour each year.

If you care at all about your organisation's systems, you won't accept anything less than Tier 3.