Green is the must-have colour of the season but when so much else is pulling focus in the market, how can you justify spending on green initiatives? The truth is that green doesn’t have to push your budget into the red and there are low cost steps that can be made individually, as resources allow, for measurable improvement. Carrie Higbie, global director of data centre solutions and services for network infrastructure experts Siemon, offers a list of practical and achievable tips for lowering carbon emissions.

Look at your applications, risk, network ports and resiliency.  Many data centres move to new locations, move to clouds, build new, thinking they are out of capacity, but many are not even close to capacity.  Every server has two network cards, two power supplies, and dual storage connections.  Which of these servers really need to have two of everything?  There are a lot of applications that would be fine if they had to manually be patched over or with a cold spare that resides on a repurposed machine. 

Understand power consumption
Look at your power consumption - and this does not mean PDU output.  You have to compare consumption to output to find out how efficiently the servers are running and when they consume power resources.  Investment in power strips can provide commissioning and power usage statistics over time.  Some servers may only need to run at certain times of the month, not continuously.  You can virtualise them, or just power cycle them using intelligent power strips which may actually provide better power savings. If you are virtualising, don’t just look at CPU consumption, look at power consumption.  Get rid of anything energy hogging first where possible. It may mean shuffling some resources, but can lead to significant savings.

Look at where your equipment is placed
An “any to all” cabling configuration will allow you to place your servers where it makes the most sense for power and cooling, not where there is an available switch port.  If you are precabled, a server can be deployed anywhere and connected via the central patching area.  It may require a little extra cabling, but if it keeps you from adding supplemental cooling the payback is excellent.

Cool not cold
Determine whether you really need all your CRAC units on and at the temperature they are set.  CRAC units operate more efficiently when they are supplied warmer air and don’t wear out as fast.  Find out the maximum operating temperature supported by your active electronics manufacturers; most will support higher temperatures than we are used to in the data centre.

Stop mixing hot/cold air
If you are in a hot/cold aisle arrangement move your cabinets together and install blanking panels everywhere you don’t have equipment. Avoid mixing hot and cold air to the air intake in your equipment.
Install brush guards or air pillows in the floor where you have cable penetrations.  The openings are typically in the rear of cabinets where you don’t want to lose a large volume of cold air. 

Dispose of old cabling
If properly designed, under floor cabling won’t have an adverse effect on your cooling.  But if allowed to get unruly not only will it hurt airflow, but you could have performance issues - particularly in UTP systems as the twists in the pairs are compromised.  Overhead systems can have the same problems if additional layers of tray are required and end up over the rear of cabinets, effectively putting a ceiling on the hot air so that it isn’t pulled out of the room by CRAC units.

Decommission
Many data centres have servers that haven’t passed traffic in a long time, but remain up and running.  Typically this is due to someone bringing up a replacement server and the old one is left up “just in case” and no one ever turned it off.  Time to decommission!

Power Rebates
Ask for rebates and support from your power provider to get more efficient technology.  Government pressure on utilities companies mean that they are stepping up to help customers make savings.

Nb:  Watch for new switches and server cards that will take advantage of Energy Efficient Ethernet over the next year.