Metrics

A metric is a quantifiable measure of only one thing or a combination of other metrics. EESR concerns itself with metrics that measure efficiency in some form or another. These metrics can generally be divided into two categories: efficiency and sustainability.

⚡Efficiency Metrics

Efficiency metrics refers to those that are only concerned with how much energy is wasted and not used productively. For instance, a Power Delivery Unit (PDU) that has an energy efficiency rating of 98% loses 2% of the input energy vs its output energy.

🌿Sustainability Metrics

Sustainability metrics on the other hand provide insight into the environmtal sustainability of the data center. Such metrics usually consider carbon dioxide emission or cleanliness of energy sources in its definition.

Mega Metrics

One of the key principles of EESR is that there is no one metric to rule them all. However we believe that there are some metrics that are worth mentioning and supporting as there underlying measures are valuable and when used correctly can provide a generic overview of efficiency. We refer to such metrics as mega metrics.

Recording Guidelines

Assessment Period

Geography can play a tremendous role on the energy use and efficiency of a data center. To prevent misleading results, most metrics are most valid when measured throughout a full year as to account for seasonal variations of climate, energy production, and load variation.

Measurement Point

It is recommended that measuring is done as close to the boundary of the definition of the metric. For instance, when measuring IT power consumption, it is best to measure the power consumption of the compute components in each server as opposed to electricity entering the server room.