Machine room
The room behind the door with the combination lock: power, cooling, cabling, emergency power, access and energy. Each part takes a metric, an obligation or a hands-on task from running data centres and server rooms and checks it against the primary source.
One part a week, on Thursdays. Sources are the German Energy Efficiency Act, the BSI IT-Grundschutz Kompendium and other legal texts. Standards such as EN 50600 are protected by copyright and are only paraphrased; draft legislation is labelled as such.
Published so far
A PUE from the data sheet is not a measurement
Topic: PUE measured, not estimated
Machine room, part 1: from 1 July 2027 a statutory PUE limit applies to existing data centres in Germany, as an annual average. Many have a PUE, but often from the data sheet, from rated power or from a cool day in February. What the Energy Efficiency Act means by the metric, where it can be flattered, and why the amendment does not change that.
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A data centre for the BSI, not for the Energy Efficiency Act
Topic: Data centre under the Energy Efficiency Act and IT-Grundschutz
Machine room, part 2: three racks in the basement, forty kilowatts, "we don't have a data centre". For the German Energy Efficiency Act that is true, because it counts kilowatts and starts at 300. IT-Grundschutz counts something else: importance for the organisation's tasks. On that basis, the only central server room is generally to be treated like a data centre. Two definitions, two different answers to the same question.
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A/B is only redundant when each side carries the load alone
Topic: A-B supply and power supply redundancy
Machine room, part 3: two power rails, two strips per rack, every server with two power supplies. On the plan, that is redundant. Whether it really is depends on three things: the load on each side, where A and B join, and the devices whose second power supply is plugged into the same strip. What IT-Grundschutz says about it and how to check.
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A forgotten server still draws power
Topic: Ghost servers and stranded capacity
Machine room, part 4: almost every server room has a device that nobody needs any more and nobody wants to switch off. It draws power, has to be cooled and occupies rack units. What the Energy Efficiency Act requires, why switching off fails on ownership, and how to find ghost servers without hitting a production server.
Read this partWhat is still to come
The order may shift, for example when the amendment to the Energy Efficiency Act is promulgated.
- Part 5: The emergency power chain and its last test run
- Part 6: Cabling documentation that is true: inventory against plan
- Part 7: Colder is not safer: the supply air temperature
- Part 8: The 2026 report is being measured now
- Part 9: Who was at the rack? Access that can be evidenced
- Part 10: Waste heat: from mandatory field to heating network
A topic from your server room?
If there is a metric, an inspection or a dependency in your organisation that nobody knows exactly about: write to us. The series lives on questions from operations.