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Finding and Merging Duplicates After Discovery

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In this lesson, you will learn:

  • Why duplicates can still appear
  • How to find them
  • How to merge safely

🔁 Quick look back: Last time: Measuring Coverage and Credential Success. You learned how coverage, credential success and duration were measured.

1 The Problem: A Duplicate Appeared in London

Even after cleanup, London’s scan created a second snwr-lon-fs-01. Why:

  • The old CI had a typo in its name.
  • It had no serial number to match on.

🎯 The problem: A duplicate appeared after Discovery ran.

👉 The fix: Find it, work the de-duplication task, and fix the cause.

Flow of de-duplication.
Figure 1. Merging the London file server duplicate.

2 Finding duplicates

  • De-duplication tasks created by IRE.
  • CMDB Health duplicate results.
  • A name search after each wave.

Key term: De-duplication task

A task IRE creates when it finds duplicate CIs, so someone reviews and merges them.

3 Merging safely

  1. Confirm it’s the same device (serial, IP).
  2. Keep the CI with the most history.
  3. Move links to the keeper.
  4. Retire the other.
  5. Fix the cause, like a bad name.

4 Project Clear View: How We Implemented It

📍 Situation: A de-duplication task appeared for snwr-lon-fs-01.

🧭 Decision: Review, merge and fix the cause.

🛠️ Steps we took:

  1. Checked both CIs: same serial number.
  2. Kept the one with incidents.
  3. Moved links and retired the other.
  4. Oliver fixed the typo on the old name record.

✅ What we verified:

  • One CI remains.
  • DEF-01 closed. AC-05 met: zero duplicate servers.

📁 Evidence: DEF-01 closed with evidence.

5 Quick recap

  • Duplicates can still appear after cleanup.
  • IRE creates de-duplication tasks.
  • Keep the CI with most history, move links, retire the other.
  • Fix the cause.

6 Check yourself

Think of your answer first. Then tap to check.

1 What caused the London duplicate? Show answer

The old CI had a typo in its name and no serial number.

2 Which CI do you keep? Show answer

The one with the most history, like incidents.

3 Which acceptance criterion does this support? Show answer

AC-05, zero duplicate servers.

Nice work! SNWR’s CMDB has no duplicate servers. 🎉
Next up: CMDB Health for Discovered CIs

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