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Shiva Charan
Shiva Charan

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⏱️ TTD - TTM - TTR Explained

#monitoring #devops #tutorial #beginners

Example to understand TTD, TTM, and TTR, it helps to walk through a realistic production incident step by step.

🧩 Scenario Example

You have an e-commerce web application running in production.
At 10:00 AM, a new deployment introduces a memory leak in the checkout service.

🔍 Time to Detect (TTD)

Definition:
The time it takes for diagnostic data about an incident to reach the development and operations teams.

📌 What happens

  • 10:00 AM – Memory usage starts increasing rapidly
  • Monitoring system collects metrics and logs
  • Alert triggers when memory crosses the threshold
  • Alert reaches the on-call DevOps engineer

⏱️ Measurement

  • Alert received at 10:05 AM 
👉 **TTD = 5 minutes**
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💡 Why it matters

  • Shorter TTD means problems are noticed faster
  • Long TTD often leads to customer-facing outages before teams even know there is a problem

🛠️ Time to Mitigate (TTM)

Definition:
The time it takes teams to act on monitoring data and reduce the impact of the incident.

📌 What happens

  • 10:05 AM – Alert received
  • Engineer checks dashboards and traces
  • Identifies checkout service memory spike
  • Scales up pods and restarts affected containers to stabilize service

⏱️ Measurement

  • Mitigation completed at 10:15 AM 
👉 **TTM = 10 minutes** (from detection to impact reduction)
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💡 Why it matters

  • Mitigation does not fix the root cause
  • It restores service availability and limits customer impact

🔧 Time to Remediate (TTR)

Definition:
The time it takes to identify and permanently fix the root cause of the incident.

📌 What happens

  • 10:15 AM – Service stabilized
  • Engineers analyze logs and traces
  • Root cause identified as a memory leak in new code
  • Code is fixed, tested, and redeployed

⏱️ Measurement

  • Fix deployed at 12:00 PM 
👉 **TTR = 1 hour 45 minutes**
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💡 Why it matters

  • TTR measures engineering effectiveness
  • Long TTR increases the chance of repeat incidents

🧠 Timeline Summary 

10:00  Issue starts
10:05  Alert received        -> TTD = 5 min
10:15  Service stabilized   -> TTM = 10 min
12:00  Root cause fixed     -> TTR = 1 hr 45 min
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🏁 Key Takeaways

  • 🚨 TTD is about visibility
  • 🛠️ TTM is about damage control
  • 🔧 TTR is about permanent resolution

High-performing DevOps teams focus on reducing all three, with particular emphasis on fast detection and mitigation to protect customers and revenue.

If you want, I can also map these metrics to SRE practices, SLIs/SLOs, or real Azure/AWS monitoring tools.

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