Home Insight Let's Talk: Generators

Hosting your servers in a colocation data centre will reduce the downtime you experience (among other benefits) and the generators they deploy are a large part of that as they can keep their racks powered even if there is a mains power failure.

[Watch Let's Talk: UPS (Uninterruptible Power Supply)]

4D - Lets Talk - Generators - ID(Subtitled)v5

What do data centre generators do?

Data centres will have their generators configured so that in the event of a mains power failure, the generators will automatically start up and feed critical power to the data floor to ensure servers and IT equipment stay online.

Generators will typically take around ten seconds to switch on, which is why UPSs are also very important

With these generators and a store of onsite fuel, a data centre has their own mini power plant. Whether power is lost for just a few minutes or it's an extended outage of over 36 hours, the generators will keep everything switched on. Additionally, a lot of data centre will have refueling contracts in place to ensure the diesel running these generators is regularly topped up, keeping them on indefintiely.

How many generators will a data centre have?

Different data centres have different numbers of generators, depending on two key factors: 

  • The power requirement of the data centre 
  • The amount of redundancy the data centre decides to have

Larger data centres with many racks will need more generators than a smaller data centre, but even data centres that are the same size could have a different number of generators. 

Some data centres will have redundant generators, that are effectively backups for if something goes wrong with their main generator.

Redundancy is expressed in N, where N is the minimum requirement to keep the data centre running.

Generators, like the ones we have at 4D Surrey, are configured with N+1 redundancy- this resilience means we have one generator that can run the whole building and, should this experience a failure, another one is ready to take over its work. 

How many generators should my data centre have?

You will need to decide the level of redundancy you would like for your colocation data centre partner to have and how you'll compare those different data centres. But once you decide the level of power redundancy you're comfortable will, you can then ask your prospective data centres about how many generators they have.

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