Time To Think of Lower Energy Networks? - by Peter Judge

Views and Opinions on Green IT (Sep 27 2010)

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   The Ethernet switches in a data center use a small proportion of the energy, but network equipment vendors say we should put some effort into cutting that energy - because the network part of the data center power load will increase over time.

    

   Virtualising the resources in a data center sets up a world of virtual servers and pools of storage. It doesn’t matter where in the data center a given process is running - you just spin up a virtual machine from disk, and run it on a physical server that has the capacity.

    

   That’s convenient - and it makes the server and storage parts of the data center hardware more efficient, because fewer machines are standing idle or are under-utilised.

    

   But as VMs start and finish, and are moved about, it increases the number of Gbyte going across the network. So it must increase the amount of power used in the switches.

    

   The network part of the data center is never going to use as much power as the servers or storage. Switches don’t have spinning disks, and a data center will have maybe one switch for more than ten servers.

    

   At a fair guess the networks in most data centers use less than ten percent of the energy - after the cooling is taken off.

    

   But the energy demands of switches can vary so much, that it’s possible to save significant money (and emissions) by cutting their energy use.

    

   Over the last year, I’ve heard this story from a couple of vendors who sell switches into the data center market., Brocade is one, and now Force10 is another -and Force10’s marketing VP Stephen Garrison showed up in London with a new report by test house Tolly to talk about.

    

   The main point for both vendors - predictably enough for networking companies - was “We’re better than Cisco. We use less energy than Cisco.”

    

   Well, I should hope so! With its incumbent position, Cisco is not a hardware trailblazer. It does have some pointers on efficient data centers - and a whole separate product family for smart grids and home energy management  monitoring.

    

   But it doesn’t give the impression of trying very hard on power usage in its data center switches (maybe it could stand a bit of bullying from a group like Greenpeace!). So any Cisco competitor that can’t beat it on that score ought to be a bit ashamed.

    

   It is certainly worth network vendors making some effort to reduce the energy demands of their products, because data centers are often so strapped for power that it limits expansion within the data center. Use less power, and you might fit more servers and switches in,

    

   And data center people are increasingly being rated on how well they cut energy. So finding a way to cut that extra bit of energy might be the difference between achieving your bonus and missing it.

    

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