What is MTTU?

DevOps engineers are constantly striving to improve all aspects that impact service performance and reliability. Recently, a new metric has come to light known as Time to Understand (TTU) or Mean Time to Understand (MTTU). This metric is a step ahead for teams that have already incorporated broader MTTA and MTTR tracking and are now looking to conduct more in-depth incident analysis.

What is TTU/MTTU?

TTU is the duration it takes for an on-call engineer or response team to comprehend the scope, impact, and root cause of an incident. It starts when an incident is first noticed and ends when the engineering team fully grasps the problem. It focuses on the cognition phase of incident response but also includes the post-incident learning period, as many incidents can be fixed before the team gets a complete understanding of the incident's cause.

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MTTU expands on this by calculating the average TTU over a set of incidents within a given timeframe. This provides a more stable metric that accounts for the natural variability of individual incidents.

Why is TTU/MTTU Important?

Understanding an issue deeply is crucial because:

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• Informed actions. It ensures that actions taken are better informed and targeted, thereby reducing the likelihood of guesswork that can potentially aggravate the situation.
• Efficiency. It allows for a more structured and effective incident response, saving precious time and resources.
• Learning and improvement. A thorough understanding of incidents leads to better postmortems and contributes to a culture of continuous learning and improvement. This also means that teams are better prepared to face new challenges.
• Performance indicators. MTTU acts as a performance indicator for alerting and monitoring an organization's infrastructure. A high MTTU may indicate that alerts should be more descriptive and prescriptive.

Reducing TTU/MTTU

To minimize TTU/MTTU, a DevOps team can employ several strategies:

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• Enhanced monitoring tools: Implement advanced monitoring tools that provide comprehensive profiling and diagnostic capabilities.
• Effective alerting mechanisms: Craft alert descriptions that include contextual information to grasp the incident’s impact quickly.
• Training and simulations: Regularly train the response team on incident scenarios to improve their understanding speed.
• Knowledge sharing: Utilize platforms like ChatOps for improved collaboration and knowledge sharing during incident response.
• Runbooks and documentation: Maintain detailed runbooks and documentation that can be easily accessed for guidance during an incident.

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By focusing on reducing TTU/MTTU, a DevOps team increases its agility and capability to manage incidents, leading to a more robust and reliable service offering.

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While metrics like MTTR (Mean Time to Repair) and MTTA (Mean Time to Acknowledge) continue to be critical in the DevOps realm, MTTU is often overlooked, especially in distributed microservice architectures. These architectures split systems into numerous independent services, increasing the complexity of diagnosing issues. In such cases, the MTTU metric can help underpin the effectiveness of the approach to incident response and ensure that teams effectively navigate the complexities of microservices. Additionally, OTel can help in improving observability in a microservice architecture.

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Embracing it within incident management practices ensures that teams are not just quick to react but also competent in understanding the challenges they face, leading to more sustainable resolutions and a mature DevOps model.

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Learn more about incident management metrics from ilert Incident Management Metrics Guide.