Get it straight: CMDB can not be auto-discovered
This line in a Butler Group white paper synopsis pressed a button for me:"Service Configuration Management enables quick establishment of Configuration Management Database (CMDB) through auto discovery". I respect the Butler Group more than most analysts, and I am too tight to buy the full text from them, so I hope the synopsis is a bit misleading. Though from the tone of the rest I fear it isn't. This pernicious idea turns up regularly, mostly from software vendors. It must be stamped out. Read my lips: CMDB CANNOT BE AUTO-DISCOVERED.
Tools auto-discover almost all the physical assets in the environment, and plot their network inter-relationships. From the same page:"Configuration management involves the identification and definition of the assets within the IT infrastructure such as switches, software, and servers, and the relationship between the various components". No it doesn't. That is only the bottom layer of a CMDB.
Most tools cannot auto-discover the software layer and the inter-relationships of software components across nodes. Web Services is making this almost impossible because it is so loosely coupled.
No tools can auto-discover the logical functions. And no tools can automatically relate those functions to processes. And no tools can automatically relate those processes to ITIL services. And no tools can automatically relate those services to business units and stakeholders. And no tools can autodiscover and relate SLAs or UCs or....
It is all manual, dammit. And that is why it can't, practically, be done.
When will people stop muddling asset databases and CMDBs? Vendors play this game all the time. They offer an asset database, call it a CMDB, and promise the benefits of a CMDB: how does discovering my network diagram help me understand what business service is impacted? Unmitigated bullshit. I expect better from Butler Group.