Iterating on IT Service

I've been watching a battle between two opposing schools of thought in the CMDB world. One says that a CMDB represents the authorized configuration of the IT Service environment. Not the real configuration, not the way the system is working now, but the authorized configuration as determined by the change board and the planning groups. The other school wants a CMDB to be as accurate a reflection as possible of the way the system is configured--right now. Not what it is supposed to be, what it is. Which is correct?

Both schools have good arguments. ITIL v2 emphasized the authorized configuration school. Clearly recording the authorized configuration is the basis for rational configuration management. You can't manage what you can't measure. (The IT Skeptic had an interesting discussion on measurement and key performance indicators (KPIs) a week or so ago: "Great myths of ITIL #1: "You can't manage what you can't measure".) Further, you can't manage what you have no record of.

On the other hand, if I am an analyst on the service desk, the first thing I want to know is how the system is configured now--not the way it is supposed to be configured. The authorized configuration might give me a clue as to why an incident occurred and restoring the authorized configuration might be a perfect resolution, but if I don't know what is actually going on, I am shooting in the dark. And that's dangerous!

Stop arguing already!! ITIL v3 very clearly distinguishes baselines from snapshots. A snapshot is the observed configuration of the IT service environment at a given instant. I like to call snapshots the "as-is" configuration. That is exactly what the poor service desk analyst needs. A baseline is the result of planning and authorized changes. Just what the configuration manager needs to manage. Both can be accommodated in a single CMDB, as long as baselines and snapshots are clearly distinguished.

Too often, I have seen CMDB practices that muddle together baselines and snapshots, trying to meet the needs of both the configuration manager and the service desk. When this happens, the service desk analysts are never quite sure if what they see in the CMDB reflects reality, and the configuration managers are never quite sure what they are managing.

Occasionally, a snapshot can be used to set a baseline. If a system is working as well today as it ever has, the IT organization may make a conscious decision to authorize the snapshot as a new baseline. But this is the exception, not the rule. Most snapshots are not baselines and baselines are not necessarily derived from snapshots.

When deciding what to house in your CMDB, you do not need to choose between snapshots and baselines. The answer is not either-or. Acknowledge that baselines and snapshots are different and serve distinct purposes. A snapshot is for troubleshooting and historical analysis, while baselines come from authorization, not observation.

Both snapshots and baselines have their roles to play and neither can do the whole job. Both sides are right.

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