An inventory tells you what you have. A CMDB tells you how everything connects. When a switch fails, the CMDB shows which servers, services and users are affected.
Inventory vs CMDB
| Aspect | Inventory | CMDB |
|---|---|---|
| Focus | What exists | How it relates |
| Data | Hardware, software, specs | Dependencies, impact, services |
| Use | Asset control | Impact analysis, change management |
Building the CMDB in GLPI
1. Start with critical assets
Servers, core switches, firewalls, storage, WAN links. These are the CIs that, if they fail, impact multiple services.
2. Create connections
In GLPI, use the Connections tab of the asset to document network connections and direct connections (monitor → computer, server → rack).
3. Link to contracts and suppliers
Each critical CI should be linked to the support contract and responsible supplier.
4. Document services
Create configuration items of type "Service" and link them to the supporting components. E.g.: "Email" service depends on: Exchange server + core switch + internet link.
Impact analysis
With the CMDB populated, when a switch fails, GLPI shows all connected servers, affected services and available support contracts. This transforms incident response.
Next step
Integrate the CMDB with change management – every change to a CI should consider the impact on its relationships.
