All the more for organisations starting out with implementing ITIL, there can understandably be some level of confusion surrounding the CMDB (Configuration Management Database) due to it's seemingly mysterious pervasiveness in supporting ITIL processes and functions.
The 'Myths of the CMDB' article by Michele Hudnall addresses some of the more common misconceptions encountered [1] along with some valuable insight.
ITIL v3 it must be said, has made endevours to extend the CMDB from what was considered ultimately a 'database' modelling the IT infrastructure, holding details of Configuration Items (CIs) thru their lifecycle, into a powerful resource more business aligned and focused. [2]
The transition to a CMS in brief encompasses the following updates:
- The CMDB was understood by many to be a single database incorporating all information possible on your IT infrastructure along with their inter-relationships; the CMS provides clearer guidance by introducing 4 layers each with it's own perspective or view of the IT infrastructure. This makes for easier comprehension and implementation.
- The CMS scope is wider than being an information repository; it includes the database part along with a tool & will provide a federated view linking all CMDB information.
- The CMS information extends to include details on customers, users, business units etc.
- The CMS concept recognises the need in some organisations for multiple physical CMDBs, but ensures the top layer (the Presentation Layer) provides a unified view showing respective layers of complexity as one drills down.
- The CMS is referred to and used by all of the IT Service Management processes
In summary, the CMS builds upon CMDB principles to reduce the scope for confusion thru a more structured and prescriptive approach to modelling and managing your IT infrastructure.
Reference(s):
[1] http://datacenterjournal.com/index.php?option=com_content&task=view&id=1477&Itemid=40
[2] http://community.ca.com/blogs/itil/archive/2007/10/26/promoting-the-cmdb-to-cms.aspx
