Greening our Servers

September 1, 2011 Technical, General

Having finished greening the office we decided to do something about the data centre as well.

To give you an idea of how much of a problem the data centre is:

  • The average Australian home uses between 20 and 30 kWh/day of electricity
  • We use around 200kWh/day in our office
  • Our data centre is using circa 4800kWh/day!
  • We do this from a foot print of around 300 square metres of floor space.

Our approach

  • Measure our usage so we can see what ¬†works and what doesn’t.
  • Source 100% green power to cover our usage
  • Reduce power consumption through increased use of energy efficient server models and virtualisation

Measuring Usage

We operate entirely on managed APC power rails, from these we collect and graph in real time the power usage of every rack we have deployed. We also aggregate the data to provide a view of total power consumption across each data centre presence.

We used the data we collected from the managed power rails to calculate power usage figures on per server level. The nature of our operations is such that server specifications vary from one machine to the next so we collected data across large set and came up with average power consumption per server figures:

  • SuperMicro servers (circa 2007 – 2010 generation 1 & 2 RU models): 210 Watts/server
  • Dell servers (R410, R510, 2010 onwards): 160 Watts/server
  • Dell servers (low voltage models): 140 Watts/server
  • Virtual machines: 10-20 Watts/server

These figures relate to physical machines with specifications varying between:

  • HDDs: 2 – 8 (SAS/SATA/SSD)
  • Memory: 2 – 64 GB
  • CPU: 1-2 (Single to Quad Core)

Green Power

The first step we took was to purchase 100% Green Power to cover the power consumption of everything in our data centre with the exception of customers co-located equipment (we took that view that with no control over their provisioning decisions this should remain the clients responsibility). Green Power is a government initiative that guarantees that all energy comes from certified, domestic renewable power generation activities such as wind, solar and hydro.

Reducing demand through virtualisation

As indicated by the figures collected above, virtualisation of servers represents the most drastic reduction in power consumption available. Aside from the operational benefits associated with virtualisation, replacing ageing server hardware with virtualised environments has not only reduced power usage but also provided significant gains in server performance.

Energy efficient Dell servers

Anchor now uses Dell servers across the board for new deployments (you can buy our old power hungry SuperMicro’s on eBay). We’ve seen a minimum of 20% reductions in power consumption by optioning new servers with:

  • Intel L series processors (low voltage variants)
  • 2.5″ drives in preference to 3.5″
  • SSD storage in preference to SAS/SATA where appropriate

As SSD storage volumes increase and price approaches that of traditional storage media deployment of SSD will increase and bring with it further reductions in power consumption. Energy efficient variant of components has been used with a view to avoiding performance degradation, for example, applications known to be CPU bound continue to be deployed on higher power CPUs and so forth.

The cost of going green

Right now the upfront costs of making the changes outlined are material, but when taken into consideration with

  • Reduced overhead of physical server management
  • Improved efficiency of new server deployments
  • Reduced costs of power and data centre space
  • Ongoing increases in power and data centre costs

and aggregated over the life of the equipment, these changes make business sense today and offer significant cost savings into the future.