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Issue with duplicate records in CMDB computers table

RMandugula
Tera Contributor

3 weeks ago

Hi Team, 

Need help in fixing the duplicate records in cmdb computers table how to merge the duplicate records and avoid duplicate entries in future

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1 REPLY 1

G Ponsekar
Tera Guru

3 weeks ago

Hi @RMandugula ,

 

Fixing duplicate records in the cmdb_ci_computer table involves a two-part strategy: remediating existing duplicates and preventing future duplicates. 
 
Part 1: Merging Existing Duplicate Records
ServiceNow provides a built-in Duplicate CI Remediator wizard to merge duplicate CIs. This is the recommended approach. 
  1. Identify Duplicates: The system automatically identifies duplicates using CMDB Health dashboards and generates de-duplication tasks.
    • Navigate to Configuration > CMDB Health Dashboard or CMDB Workspace (Management tab).
    • Review the "Duplicate CIs" panel to see a list of unhandled duplicate CIs and associated de-duplication tasks.
  2. Remediate Duplicates:
    • Open a specific de-duplication task.
    • Use the Remediate button and follow the built-in wizard.
    • The wizard guides you through selecting the "master" CI record to keep, which attributes/relationships to retain from the duplicates, and which records to delete or retire.
    • You can also use De-duplication Templates to apply consistent merging logic to large numbers of similar duplicates in a single action. 
 
Part 2: Avoiding Future Duplicate Entries
Preventing future duplicates requires ensuring the Identification and Reconciliation Engine (IRE) is correctly configured for your data sources. Duplicates typically occur due to weak identification rules or integration issues. 
  1. Strengthen Identification Rules:
    • Navigate to CI Class Manager > cmdb_ci_computer > Identification Rule.
    • Ensure the identification rule uses strong, unique identifiers that are unlikely to change or be shared, such as:
      • Serial Number (highly recommended for hardware)
      • Fully Qualified Domain Name (FQDN)
      • BIOS UUID
    • Avoid using only weak identifiers like IP address or hostname, which can be dynamic or reused.
  2. Configure Reconciliation Definitions:
    • If using multiple data sources (e.g., Discovery, SCCM import), prioritize authoritative sources in the Reconciliation Definitions to determine which data source "wins" when conflicts arise.
  3. Monitor CMDB Health:
    • Regularly monitor the CMDB Health Dashboard for new duplicate tasks. This provides ongoing governance and helps catch issues early.
  4. Review Data Sources:
    • If a specific integration or Discovery source is consistently creating duplicates, investigate that source's configuration (e.g., ensure unique webhooks, adjust discovery schedules to avoid overlaps).

 

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Thanks, GP