Home > ITIL the Elephant in the room > The CMDB. What’s Not To Love?

The CMDB. What’s Not To Love?

Oh the promise of it. The CMDB, in principle, is an entity of great aspiration and beauty.

Simply the idea that we could have a single source of truth for our entire managed infrastructure. A model containing all the entities under management and their interdependent relationships to each other.

Have a Fault? Simply use the CMDB to not only isolate the cause but also highlight the impact, internally within our IT realestate and the effects of the fault on our end-users and customers.

Receive a request to support a new service? The CMDB will show us whether we have the capacity to support it, enable us to quickly identify the managed entities which will support the new service or, show us where the changes need to come, what will be impacted by the changes and then contain the changes to the infrastructure once complete.

The CMDB was conceived with the Mainframe, had its gestation with the tail end of Client-Server computing and has become the in-vogue answer to all IT problems since the advent of dynamic computing.

The problem is, it is not the answer.

If you have a CMDB (or a central config reference source database) ask yourself: “How accurate is my data?”

We know from our own experience in our companies that our CMDB completeness ranges from ~15% [I kid you not!] to a claimed ~70%. The average amongst us though is a rolling ~45% accuracy, but, we all note that it is getting harder and harder to even maintain what we have as our infrastructures are partially outsourced and we look to utilize hybrid Cloud services across the piste.

The real problem we have though is that at a given point in time we do not reliably know which of the records in our CMDB are truth.

The reality is that we are unable to complete a Version 1 CMDB which we can then change manage. Unlike painting the Forth Road or Golden Gate Bridges, where once we finish painting the bridge, we start from the beginning and paint it again, if the CMDB were a bridge, we would paint part of the deck, part of the pylons, part of the cables, and while we are painting, parts of what we have painted will be replaced and parts are are in the middle of painting will be replaced. Not only do we never get a model of our infrastructure to start with, we never ever get a model, period.


  1. July 5, 2013 at 5:12 am

    Sweet blog! I found it while searching on Yahoo
    News. Do you have any suggestions on how to get listed in Yahoo News?
    I’ve been trying for a while but I never seem to get there! Thanks

  1. March 2, 2012 at 4:14 pm

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