Skip to tutorial content
Rate module Not yet rated

Why Discovery Depends on a Healthy CMDB

4 min read
On this page

In this lesson, you will learn:

  • What Discovery does to a messy CMDB
  • The three things to check before scanning
  • Why this comes before design

🔁 Quick look back: Last time: Writing and Signing Off the Requirements. You learned how to write, trace and sign off the requirements.

1 The Problem: Discovery Can Make a Messy CMDB Worse

SNWR’s CMDB was built by hand from a spreadsheet. If you point Discovery at it now:

  • Hand-made CIs with odd names won’t match, so Discovery creates duplicates.
  • Good manual data, like support groups, could be overwritten.
  • Old servers stay ‘Operational’ forever.

🎯 The problem: Discovery can make a messy CMDB worse.

👉 The fix: Check and clean the CMDB before the first scan, and design the rules that protect it.

Compare messy CMDB outcome vs prepared CMDB outcome.
Figure 1. What happens when Discovery meets a messy CMDB versus a prepared one.

2 Three things to check first

  1. Duplicates. Are some servers already in the CMDB twice?
  2. Matching data. Do CIs have serial numbers or clean names that IRE can match?
  3. Other sources. Which imports or people write to the same CIs?

💡 Good to know: Need a refresher? See Fundamentals › CMDB Essentials › CMDB Health & Maintenance for CMDB health basics.

3 Why before design

What you find decides design choices: identification rules, which source wins, and what to clean first.

⭐ Remember: Clean first, then scan. It’s much harder to clean after thousands of scans have run.

4 Project Clear View: How We Implemented It

📍 Situation: Hana wants to start scanning soon. The CMDB hasn’t been checked in years.

🧭 Decision: Add a CMDB readiness step in weeks 2-3, before design.

🛠️ Steps we took:

  1. Explained to Hana what a messy CMDB does to Discovery.
  2. Agreed three checks: duplicates, matching data, other sources.
  3. Booked two sessions with Hana to go through the CMDB.
  4. Added a readiness review meeting at the end of week 3.

✅ What we verified:

  • Hana agreed to clean before scanning.
  • The readiness review is in the plan.

📁 Evidence: The CMDB readiness task in the plan (see CMDB Readiness › The Project Clear View CMDB Readiness Review).

5 Quick recap

  • A messy CMDB leads to duplicates and overwritten data.
  • Check duplicates, matching data and other sources first.
  • What you find shapes the design.
  • Clean first, then scan.

6 Check yourself

Think of your answer first. Then tap to check.

1 What can happen if Discovery meets hand-made CIs with odd names? Show answer

They don’t match, so Discovery creates duplicates.

2 Name the three things to check first. Show answer

Duplicates, matching data and other sources.

3 Why check the CMDB before design? Show answer

The findings decide identification rules, source precedence and cleanup.

Nice work! You know why the CMDB comes first. 🎉
Next up: CI Classes Discovery Will Populate

Was this lesson helpful?

Have a question or doubt?

Ask here and get help from instructors and fellow learners.

0 / 300

Only logged-in learners can post.