Original Research

Downtime Severity Levels (DSL)

A way to measure the Impact and Depth of Downtime in Data Centers — distinguishing inherent and non-inherent downtimes across components, systems, critical rooms, and the full site.

Definition

What are Downtime Severity Levels (DSL)?

Downtime Severity Levels or DSL is a scale that measures the severity of a Data Center downtime according to its impact level. It is designed to be used for Critical Essential Systems.

It is a seven-level scale that classifies the severity of the Data Center downtime according to:

Causes of Downtime: These can be related to Inherent Events (Preventive Maintenance, Failures / CM, Critical Events) or Non-inherent Events (Catastrophic Event, Catastrophic Failure).

Depth of Impact: The location affected by the maintenance/failure or by any other internal/external event related to Structures, Systems, and Components (SS&C).

● DATA CENTER CRITICAL SYSTEMS

Critical Essential Systems are the basis for Data Center Availability

Electrical System

CRITICAL ESSENTIAL

Cooling System

CRITICAL ESSENTIAL

Telco System

CRITICAL ESSENTIAL

Security

CRITICAL ATMO-ARCHITECTURAL

Safety

CRITICAL ATMO-ARCHITECTURAL
COMPUTER ROOM · DATA ENVIRONMENT · SITE

Critical Essential Systems are the minimum necessary services to sustain Data Center availability. If any one of them fails, the entire availability is at risk of incidents.

The 7-Level Scale

DSL and Depth of Impact of Downtime

The DSL was designed as a communication tool, in order to unify and categorize the severity of any event/incident that occurs from a single Component, to a System, Structure, or full Data Center.

Inherent Downtimes
Depth of Impact
Catastrophic Downtimes
DSL 0
No Downtime
Baseline state — no downtime recorded.
Baseline
DSL 1
Component PM
Planned Preventive Maintenance affecting an individual component.
Inherent
DSL 2
Component Failure / CM
Corrective Maintenance triggered by a single-component failure.
Inherent
DSL 3
System PM
Planned maintenance impacting an entire system (electrical, cooling, telco).
Inherent
DSL 4
System Failure / CM
System-level failure requiring corrective maintenance.
Inherent
DSL 5
Critical Downtime
Failure propagates to one or more critical environments / rooms.
Inherent
DSL 6
Catastrophic Event
Catastrophic non-inherent event impacting the site (external or environmental).
Catastrophic
DSL 7
Catastrophic Failure
Building-level catastrophic failure, including outside service dependencies.
Catastrophic
No Downtime = "DSL 0"

Catastrophic Events

Catastrophic Events refer to large-scale events that go beyond regular operations — natural disasters, fires, floods or events that impact the entire site.

Catastrophic Failures

Catastrophic Failures refer to the conditions of a Structural element that creates a building-level impact, including outside services dependencies.

Featured Publication

Downtime Severity Levels Article was selected as Cover for 7×24 Exchange Magazine 2023 Spring Issue

Article published by 7×24 Exchange Magazine, written by SERES research team.

Read the published article