Maintain the service system to ensure the continuation of service delivery.


Operational service systems should be maintained to ensure a continuing capability to deliver services in accordance with service agreements over time. This practice can encompass a variety of types of maintenance, including the following:

  • Corrective maintenance (i.e., correcting and repairing components that degrade the operational capability of the service system)
  • Preventive maintenance (i.e., preventing service incidents and defects from occurring through pre-planned activities)
  • Adaptive maintenance (i.e., adapting the service system to a changing or different service delivery environment)
  • Perfective maintenance (i.e., developing or acquiring additional or improved operational capability of the service system)

Corrective maintenance can be performed to address service incidents or to resolve their underlying causes.

Depending on the type and scope of actual instances of service system maintenance, other process areas can contribute practices that are relevant to accomplishing this effort, especially for any maintenance that has the following characteristics:
  • Represents a change to the requirements or design of the service system (e.g., perfective maintenance)
  • Entails significant risks to implement changes required by maintenance activities

Maintenance can be performed on any portion of a service system, including consumables, processes, and people. The maintenance of people as service system components is often accomplished through training, although other methods can be appropriate as well (e.g., transferring staff members to roles that better match their skills).


SSD Addition
Refer to the Service System Development (SSD) (CMMI-SVC) process area for more information about developing and analyzing stakeholder requirements.

Refer to the Service System Transition (SST) (CMMI-SVC) process area for more information about preparing for service system transition.

Refer to the Configuration Management (CM) (CMMI-DEV) process area for more information about tracking and controlling changes.

Example Work Products

  1. Corrective or preventive maintenance change requests
  2. Maintenance notifications
  3. Preventive maintenance schedules


1. Review maintenance requests and prioritize requests based on criteria identified when establishing the service delivery approach.


SSD Addition
Significant maintenance activities—ones that result in changes to the requirements or design of the service system—benefit from Service System Development practices as well.

2. Analyze impacts on service systems and services delivery.

3. Develop a plan to implement maintenance.

Non-routine maintenance requests should be scheduled into agreed maintenance slots to ensure that the availability of services is not adversely affected.

4. Release maintenance notifications to relevant stakeholders.

5. Update service system documentation as appropriate.

6. Implement and test corrective or preventive maintenance according to the plan and operating procedures.

Testing should be performed outside the service delivery environment when appropriate. Significant maintenance changes to a service system should apply Service System Transition practices as well.

7. Submit maintenance documentation and configuration changes to a configuration management repository.