When it becomes available, the Server Idle Coefficient (SIEC) metric from the German Environmental Agency may also be used (under development with the SDIA).
Background on the metric (can be deleted later):
ITEUsv describes the utilization of the server equipment in the DC in operational conditions. ITEUsv is developed with the knowledge that server energy efficiency tends to be optimal with higher utilization level. ITEUsv accounts for utilization (the amount of time the server is actually doing work) and power management (the ability of the server to reduce the energy consumption when the server is not fully loaded) aspects.
- ITEUsv(t) is the average Central Processing Unit (CPU) utilization of all servers or a group of servers in a DC at time t.
- It corresponds to the sum of the CUSi(t) divided by N, with:
- CUSi(t): CPU utilization ratio of server i at time t, measured by a performance monitoring tool provided by a server operating system
- N: the number of servers in a DC or in a group running at time t
- When some servers are working at very low load, a DC owner/operator can improve ITEUsv(t) by reducing the number of operating servers with virtualization techniques, while maintaining the whole workload of the C.
- If a DC owner/operator utilizes server “power OFF” function to save energy consumption of servers in idle state, ITEUsv(t) shall be calculated by subtracting servers at “power OFF” state.
- The ITEUsv(t) value is high when most servers are running at high utilization status at time t.
- ITEUsv indicates average CPU utilization in a year for all servers or a group of servers.
- The DC shall monitor ITEUsv(t) for a year and collect all data. The DC shall then calculate the annual average of ITEUsv(t), which is the ITEUsv.
- The interval of measurement shall be between 1 min and 1 h. The DC shall decide the interval based upon server operating conditions.
- In case the measurement is made in a partial section of the DC or a group of servers in a DC, then the measured area shall be stated. This group shall be identical and designated to a measurement group of ITEEsv. ITEUsv shall not be summed among these groups. When there is no CPU monitoring tool applicable to some servers, these servers shall not be included in these groups.
- During the measurement, the maximum value of ITEUsv(t) and its time shall be recorded. The maximum value of ITEUsv(t), or peak ITEUsv(t), is useful to set a target value of ITEUsv