Posts Tagged ‘Metric’

Sensors

Thursday, October 8th, 2009

Since I’m on the subject of facility, I might as well cover a few more points on data center facility, measurement and sensors.  When I think about sensors, it reminded me of my first job.  I used to be with a Systems Integrator, working on Plant Information Management Systems (PIMS) for refineries, gas plants, utilities, etc.  I remember once, I was 120km west of Doha, Qatar, and was commissioning the PIMS system together with my customer and main contractor. It was August, in the mid-90’s.  We were going through the screens and data points / tags with values collected from field instruments in the plant via their Distributed Control System (DCS).

Operator-Console As we review the data points, we came across a few thermocouples out in the plant indicating measurements of 54′C to 60′C.  Although it was a hot summer day, a reasonable reading for those tags should be in the range of 45′C to 50′C.  It was an interesting anomaly…

For a gas plant, it is very critical that the plant data collected are accurate as the data are used for planning purposes, production controls, yield accounting, and many other forms of analysis.

For a data center, data accuracy is also equally important.

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PUE (part 2)

Sunday, September 6th, 2009

Following up on my previous post regarding PUE.  What does it mean for an organization to have a low or high PUE?

PUE = (Total data center facility + IT equipment power utilization / Total IT equipment power utilization)

where PUE is a ratio, e.g. a PUE of 1.5 means that for every 1kW of IT equipment (be it server, network devices, firewalls, etc.), it would require 0.5kW of power to keep the data center operating to maintain sufficient cooling, de-humidification / humidification, availability (UPS), etc. to sustain and house the said IT equipment.

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PUE (part 1)

Saturday, September 5th, 2009

There is a saying “what you can’t measure, you can’t manage”.

When it comes to the data center facility, the Green Grid recommended using PUE (Power Usage Effectiveness) as a metric to measure data center efficiency. PUE is quite widely adopted in the industry today. It was intended (and still is) to be a simple metric for data centers that is easy to understand and use, that enables DC operators and IT administrators to quickly estimate the energy efficiency of their data centers, compare the results against other data centers, and determine if any energy efficiency improvements can be made or if there are potential problems. The PUE metric – which is the ratio of a facility’s total power to the power being drawn by IT equipment – requires complete knowledge and understanding of each component in the data center and its power consumption.

However, if you would analyze the ratio carefully, you realize a catch. “Power being drawn by IT equipment” – this is a variable number. IT equipment’s power consumption varies from time to time, depending on their utilization. For example, a server with 10% utilization will consume less power than a server utilized at 90% level.

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