I’m going to return to the subject of the Configuration Management Data Base (CMDB) for this post, prompted by a customer that invited me to look at their CMDB.
ITIL makes a distinction between Asset Management and Configuration Management (the CMDB is what you get from an effective Configuration Management process). I’ll avoid quoting directly but it defines the two thus:
Asset Management: Accounting for IT assets for accounting or managerial purposes. This might include maintaining a list of items so that you know when warranties expire, or so you can perform some routine upgrade planning.
Configuration Management: Provide a logical model of all the Configuration Items within the organisation, showing how the combine and depend on each other to provide services to users.
In practice, this means that the two are quite different.
Asset Management is typified by lists of computers. These generally are not linked together to show much more than the machine and some peripherals attached (such as a monitor or printer). In an Asset Management system, it is sometimes hard to see server equipment amonst all the desktops, and you don’t see ‘virtual’ items such as web server instances or database server instances.
Configuration Management is typified by diagram rather than lists (though lists do exist of course). This is why Serio expresses the CMDB in graphical terms. The diagram shows a variety of items and shows how they link together and depend upon each other so that, for example, you can see the effects of shutting down a database server. The CMDB will typically have tangible and virtual items on it like I’ve mentioned above, and will show how items combine together to deliver customer services.
I’ll probably post more about this on Friday, but I’ll pose the question: how can you support an IT infrastructure that is not documented?