CMDB

A CMDB answers the question of which IT components exist and how they are connected. That helps in operations and at the end of the lifecycle, when servers, storage systems or notebooks are decommissioned. Here you can read what a CMDB is and why it is often forgotten during decommissioning.

What is a CMDB?

The term comes from ITIL, a widely used framework for IT service management. Every element that has to be managed for an IT service is called a configuration item (CI) there, in German Konfigurationselement. This can be a physical server, a virtual machine, an application, a contract or documentation.

For each CI, the CMDB stores properties such as type, version, location and owners, but above all relationships: application A runs on server B, which is attached to storage system C. These dependencies make the difference from a mere inventory list. CMDBs are usually part of IT service management software and are often populated automatically by discovery tools in the network.

CMDB, ITAM and inventory compared

Approach	Focus	Typical questions
CMDB	Technical configuration and dependencies	Which services fail when this server is switched off?
IT Asset Management (ITAM)	Financial and contractual lifecycle	What did the device cost, when does the warranty or lease end?
IT inventory	Complete recording of the inventory	Which devices exist, where are they located, who are they assigned to?

In practice, the three areas overlap. Many companies manage devices both as an asset and as a configuration item. A common identifier is important, usually the serial number or Inventory number.

What to note when retiring devices

Before a server or storage system is dismantled, the CMDB shows which applications and services depend on it. This allows the shutdown to be planned without a service failing unexpectedly. Afterwards the work on the database itself begins:

• Change the status: The CI is marked as "out of service" or "decommissioned", not simply deleted. That way the history is preserved.
• Record data carriers: For servers and storage systems, the built-in hard drives should be known together with their serial numbers so that erasure proofs can be assigned.
• Link proofs: Erasure or destruction certificates are stored on the CI or the asset.
• Clean up dependencies: References to the old device are removed or switched to the successor system.

A CMDB that continues to list decommissioned devices as active quickly loses value. It is then no longer a reliable source for audits either. How decommissioning fits into an orderly lifecycle is described in the guide IT Lifecycle Management.

CMDB data during decommissioning with Second IT

For decommissioning with Second IT, an export from your CMDB or your asset management as a device list is sufficient. At goods receipt, every device is registered by serial number and, after erasure with Blancco, documented with a digitally signed erasure certificate. You can assign these proofs to your records. As part of the Consulting Second IT also supports inventory analysis and market valuation.

Frequently asked questions about the CMDB

What does CMDB stand for?

CMDB stands for Configuration Management Database. It refers to a database for IT configuration items and their relationships to one another.

Is a CMDB the same as an inventory list?

No. An inventory list shows what exists. A CMDB additionally shows how components are connected and which services they support. For decommissioning, however, an export from the CMDB can serve as an inventory list.

Should I delete decommissioned devices from the CMDB?

Better not immediately. It is usual to change the status and document the removal with date and proof. That way it remains traceable which device left when and how.

What is the difference between a CMDB and IT asset management?

A CMDB shows the technical configuration and the dependencies between components. IT asset management looks at the financial and contractual lifecycle, such as warranty or leasing. In practice the two overlap. A common identifier such as the serial number connects them.

How does the CMDB help before a server is dismantled?

The CMDB shows which applications and services depend on the server. This allows the shutdown to be planned without a service failing unexpectedly. After dismantling, you change the status of the entry and store the erasure or destruction proofs.