Reducing Data Centre Power Consumption - Why Virtualisation is not Enough!

The rapid growth of High Density computing has led to increased power demand that, particularly in metropolitan areas, can not always be met by the electricity supply. New technology such as "Virtualisation" is reducing the rate of increase of High Density computing hardware but power consumption in data centres continues to out grow supply. Rising energy costs and political and regulatory pressure to reduce power consumption is creating a demand for IT professionals to consider new ways of managing and reducing power consumption by servers and IT equipment.

In many Data Centres a limited supply of electricity and inaccurate hardware power consumption data restricts the number of servers that can be powered. This in turn restricts the growth of the business and has caused many companies to build or lease new Data Centre space prematurely at increased costs to the business.

If you haven't already virtualised then you have almost certainly considered the technology. Undoubtedly Virtualisation offers many benefits and should reduce your energy bills. However it is not going to make the problem of making your Data Centre more efficient go away!

It is an important tool but it should not be your only tool.

You might need fewer servers after you have virtualised but the ones you have will be very hungry beasts! They will consume huge amounts of power and need huge amounts of power to keep them cool. Over a 2-3 year period your servers will cost more to run then they do to buy!

Virtualisation does NOT resolve your power problems.

Virtualised servers are no better at reporting real power consumption, without accurate consumption data you can't calculate Data Centre Capacity or Efficiency, and while the choice of server is important, the Efficiency rating of your data centre will double or even triple the cost of running your servers.

Shouldn't you ensure you are managing that cost?

Server Running Costs

The most efficient high performance servers provided by HP, Dell or Fujitsu will use approximately 250-300 Watts (0.25KW) at 80% load.

At current energy prices of 12p/KWh this will cost you; 0.25 x 24 x 365 x 0.12 = £262 per year

It will produce over 1 tonne of CO2 per year (CO2 emissions of 0.43 - 0.55KG per KW/h)

Once you have factored in the cost of the cooling, energy loss, lighting etc in your Data Centre these costs must be multiplied by a factor of 1.5 to 3 depending on the efficiency of your Data Centre.*

Typical costs for a Virtualised environment in a moderately efficient Data Centre:

£525 per server per year
2 tonnes CO2 emissions per server per year

Factor in predicted energy cost rises over the next 4 years and you could be looking at £825 per server per year or even over £1,250 per server if you don't get your Data Centre managed effectively.

* Data Centre Efficiency is usually measured by the Power Utilisation Efficiency (PUE) rating. PUE = Total Energy Consumed (cooling, lighting, losses etc) / Energy consumed by IT equipment (Servers etc)

So how do you manage Data Centre costs and ensure they are kept to a minimum?

What you can't measure you can't manage!

You need to be able to measure consumption accurately down to the level of each individual asset using intelligent PDU's because manufacturer's plate values are inaccurate and unpredictable.

Use per outlet monitored intelligent rack PDU's to provide real time energy consumption data to enable you to:

Calculate the real capacity of your Data Centre and help you get more equipment in your existing Data Centre.
Predict faults by identifying unusual consumption.
Identify under utilised equipment.
Measure the true operating costs of your equipment.

Sweat your Assets

UPS and IT Equipment runs more efficiently at 80-100% load. Don't over specify your servers. Steady state components such as RAM consume power even when not in use.

Turn up the Heat

Raise the temperature - servers don't need to freeze. A one degree rise in temperature can save you 4% on your energy bill!
Pay attention to small details - blanking panels, floor tiles - to ensure good air flow.
Partition the Data Centre so that you only cool what needs to be cooled.
Use Hot Aisle/Cold Aisle containment systems.
Use Free Air Cooling. Even in older inefficient Data Centres you could put lower output equipment in non cooled racks.