Hi Everyone,
I'm currently investigating an issue in our ServiceNow CMDB where some expected CIs are missing.
After reviewing the data, I found that multiple entries in the CMDB Serial Number table (cmdb_serial_number) and multiple records in the Source table (sys_object_source) appear to be associated with and updating the same CI. As a result, different devices that should exist as separate CIs seem to be getting consolidated into a single CI record.
For example:
- Device A and Device B exist as separate devices in the source system.
- Each device has its own hostname, serial number, and source record.
- However, in CMDB, both source records end up updating the same CI.
- The other expected CI is never created, which results in a missing CI in the CMDB.
I would like to understand the following:
- What are the best practices for investigating and correcting this issue?
- How should incorrect records in cmdb_serial_number and sys_object_source be handled?
- Is it recommended to delete incorrect serial number relationships and source mappings so that the next import/discovery can create the missing CI correctly?
- What are the common causes of multiple source records updating a single CI?
- Are there any recommended approaches to prevent this from recurring, particularly when using SCCM/Import Sets/IRE?
