Foreword

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This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 39, Sustainability, IT and data centres.

This second edition cancels and replaces the first edition (ISO/IEC TS 22237-31:2023), which has been technically revised.

The main changes are as follows:

Annex B was added to provide dependability data for items of data centre infrastructures;
all subsequent annexes were reviewed and reordered;
terms and definitions were clarified.

A list of all parts in the ISO/IEC 22237 series can be found on the ISO and IEC websites.

Any feedback or questions on this document should be directed to the user’s national standards body. A complete listing of these bodies can be found at www.iso.org/members.html and www.iec.ch/national-committees.

Introduction

The various parts of the ISO/IEC 22237 series reference four qualitative Availability Classes as well as structural definitions to categorize different designs. The documents also refer to resilience criteria in order to improve structural requirements for a qualitative approach.

In order to meet the requirements for evaluating or comparing different designs or for validating service level agreements (SLAs) for data centres, this document introduces quantitative metrics as key performance indicators (KPIs). The proposed KPIs cover resilience attributes, including dependability and fault tolerance metrics. The characteristics of aging of infrastructures are covered by reliability criteria.

Through the use of KPIs, the comparison of designs, functional elements and components of infrastructure designs becomes possible. In addition, it is possible to optimize data centre infrastructures (DCIs) with holistic targets. It is recommended to use the KPIs of this document in combination with the efficiency and sustainability KPIs of the ISO/IEC 30134 series.

ISO/IEC 22237-1:2021, Annex A, demonstrates that a single KPI, such as Availability, is not sufficient to describe the complexity of a DCI. In recognition, this document has been developed in order to compare and value different designs with different Availability Classes of DCIs based on a set of selected KPIs.

Furthermore, this document has been created to establish KPIs for resilience of DCIs with defined resilience levels. The resilience objectives can vary depending on the outcome of the ISO/IEC 22237-1 risk analysis, the process criticality of the end user's information technology equipment (ITE), and the data centre type of business.

Using the different stages of a data centre design process, this document describes in which phases the application of KPIs for resilience is appropriate. With its assistance, data centre designers, planners and operators will be supported in defining resilience levels, performing theoretical assessments and designing and operating DCIs which are able to meet SLAs.

1 Scope

This document:

defines metrics as key performance indicators (KPIs) for resilience, dependability, fault tolerance and availability tolerance for data centres;
covers the data centre infrastructure (DCI) of power distribution and supply, and environmental control;
can be referred to for covering further infrastructures, e.g. telecommunications cabling;
defines the measurement and calculation of the KPIs and resilience levels (RLs);
targets maintainability, recoverability and vulnerability;
provides examples for calculating these KPIs for the purpose of analytical comparison of different DCIs.

This document does not apply to IT equipment, cloud services, software or business applications.

2 Normative references

3 Terms, definitions, symbols and abbreviated terms

3.1 Terms and definitions

3.2 Symbols and abbreviated terms

4 Area of application

4.1 General

4.2 DCI service definition

5 Resilience considerations as part of the life cycle

5.1 Implementation in the design process

5.2 Documentation during operation

5.3 Documentation of resilience level

5.4 Documentation of dependability

5.5 Documentation of fault tolerance

5.6 Documentation of availability tolerance

6 Determination of KPIs for resilience

6.1 General

6.2 Structuring of the KPIs for resilience

6.3 Dependability

6.4 Fault tolerance

6.5 Availability tolerance

6.6 Resilience level (RL)

6.7 Application to data centre infrastructures

Bibliography