It has been some time since we last compared the green credentials of our virtual servers to their physical cousins. When we last did the analysis in 2008 our standard VPS 5 used about one-third of the power used by a comparable physical server.
The reason for this is that a virtual server is hosted on shared hardware and does not suffer use stuff like the power suppy unit and the motherboard etc. on its own. This means that the relative power savings get bigger when the required capacity gets smaller. This was confirmed by the numbers: The 2008 VPS 4 was more than 5 times as efficient as its physical peer.
We wanted to see how our current virtual servers would hold up against modern physical servers in a low power consumption battle. It should be an exciting competition because we did see a dramatic reduction in server power consumption over the last two years as green technologies are making it into the mainstream.
This week we could not contain ourselves anymore, requisitioned some hardware and started testing. What we found is that the difference is even more dramatic than in 2008. Even though a VPS 5 is now much larger, it currently uses only a quarter of the power used by its physical equivalent. The reason for the increasing difference seemst to be that the powerful servers that are used in virtual server clusters have been getting greener faster than the smaller servers.
Below are some results from our research.
|VPS 4||VPS 5||VPS 6|
|Ampere usage server||0.55||0.60||0.65|
|Ampere usage VPS||0.07||0.14||0.22|
|Ampere power saving VPS||0.48||0.46||0.43|
|Percentage power saving||86.9%||76.0%||66.8%|
You can see quite a difference in power consumption. This difference matters: The physical equivalent of the VPS 5 is using 0.6 Ampere, enough to keep a 140 Watt lamp burning continuously.
The break-even-point, where there is no longer a difference between the power consumption of a virtual server and the comparable physical one is roughly around 64 Gig RAM and 4 large SAS harddisks. When the required capacity is smaller than that a virtual server is the greener alternative.
It seems that cloud servers are getting increasingly difficult to beat when it comes to maintaining a green infrastructure. The flexibility to allocate unused capacity to a new customer or project has not even been taken into consideration yet. We still believe that using the cloud to efficiently deploy computing capacity has a much more significant environmental impact than all the green datacenters could possibly produce.
Read more about this in our knowledgebase.