DORA - Median Time to Restore Service

What is this metric?

The time to restore service after service incidents, rollbacks, or any type of production failure happened.

Why is it important?

This metric is essential to measure the disaster control capability of your team and the robustness of the software.

Which dashboard(s) does it exist in

DORA dashboard. See live demo.

How is it calculated?

MTTR = Total incident age (in hours)/number of incidents.

If you have three incidents that happened in the given data range, one lasting 1 hour, one lasting 2 hours and one lasting 3 hours. Your MTTR will be: (1 + 2 + 3) / 3 = 2 hours.

Below are the benchmarks for different development teams from Google's report. However, it's difficult to tell which group a team falls into when the team's median time to restore service is between one week and six months. Therefore, DevLake provides its own benchmarks to address this problem:

Groups	Benchmarks	DevLake Benchmarks
Elite performers	Less than one hour	Less than one hour
High performers	Less one day	Less than one day
Medium performers	Between one day and one week	Between one day and one week
Low performers	More than six months	More than one week

Source: 2021 Accelerate State of DevOps, Google

Data Sources Required

• Deployments from Jenkins, GitLab CI, GitHub Action, BitBucket Pipelines, or Webhook, etc.
• Incidents from Jira issues, GitHub issues, TAPD issues, PagerDuty Incidents, etc.

Transformation Rules Required

Define deployment and incident in data transformations while configuring the blueprint of a project to let DevLake know what CI/issue records can be regarded as deployments or incidents.

SQL Queries

If you want to measure the monthly trend of the Median Time to Restore Service as the picture shown below, run the following SQL in Grafana.

with _incidents as (
-- get the number of incidents created each month
    SELECT
      distinct i.id,
        date_format(i.created_date,'%y/%m') as month,
        cast(lead_time_minutes as signed) as lead_time_minutes
    FROM
        issues i
      join board_issues bi on i.id = bi.issue_id
      join boards b on bi.board_id = b.id
      join project_mapping pm on b.id = pm.row_id
    WHERE
      pm.project_name in ($project)
        and i.type = 'INCIDENT'
        and i.lead_time_minutes is not null
),

_find_median_mttr_each_month_ranks as(
    SELECT *, percent_rank() over(PARTITION BY month order by lead_time_minutes) as ranks
    FROM _incidents
),

_mttr as(
    SELECT month, max(lead_time_minutes) as median_time_to_resolve
    FROM _find_median_mttr_each_month_ranks
    WHERE ranks <= 0.5
    GROUP BY month
),

_calendar_months as(
-- deal with the month with no incidents
    SELECT date_format(CAST((SYSDATE()-INTERVAL (month_index) MONTH) AS date), '%y/%m') as month
    FROM ( SELECT 0 month_index
            UNION ALL SELECT   1  UNION ALL SELECT   2 UNION ALL SELECT   3
            UNION ALL SELECT   4  UNION ALL SELECT   5 UNION ALL SELECT   6
            UNION ALL SELECT   7  UNION ALL SELECT   8 UNION ALL SELECT   9
            UNION ALL SELECT   10 UNION ALL SELECT  11
        ) month_index
    WHERE (SYSDATE()-INTERVAL (month_index) MONTH) > SYSDATE()-INTERVAL 6 MONTH 
)

SELECT 
    cm.month,
    case 
        when m.median_time_to_resolve is null then 0 
        else m.median_time_to_resolve/60 end as median_time_to_resolve_in_hour
FROM 
    _calendar_months cm
    left join _mttr m on cm.month = m.month
ORDER BY 1

If you want to measure in which category your team falls into as in the picture shown below, run the following SQL in Grafana.

with _incidents as (
-- get the incidents created within the selected time period in the top-right corner
    SELECT
      distinct i.id,
        cast(lead_time_minutes as signed) as lead_time_minutes
    FROM
        issues i
      join board_issues bi on i.id = bi.issue_id
      join boards b on bi.board_id = b.id
      join project_mapping pm on b.id = pm.row_id
    WHERE
      pm.project_name in ($project)
        and i.type = 'INCIDENT'
        and $__timeFilter(i.created_date)
),

_median_mttr_ranks as(
    SELECT *, percent_rank() over(order by lead_time_minutes) as ranks
    FROM _incidents
),

_median_mttr as(
    SELECT max(lead_time_minutes) as median_time_to_resolve
    FROM _median_mttr_ranks
    WHERE ranks <= 0.5
)

SELECT 
    case
        WHEN median_time_to_resolve < 60  then "Less than one hour"
    WHEN median_time_to_resolve < 24 * 60 then "Less than one Day"
    WHEN median_time_to_resolve < 7 * 24 * 60  then "Between one day and one week"
    WHEN median_time_to_resolve >= 7 * 24 * 60 then "More than one week"
    ELSE "N/A.Please check if you have collected deployments/incidents."
    END as median_time_to_resolve
FROM 
    _median_mttr

How to improve?

• Use automated tools to quickly report failure
• Prioritize recovery when a failure happens
• Establish a go-to action plan to respond to failures immediately
• Reduce the deployment time for failure-fixing