CMDBuild is described as 'enterprise system: Java server-side Web GUI Ajax, SOA-based webservice. All reusing open source technologies and following industry standards'. There are five alternatives to CMDBuild for a variety of platforms, including Windows, Linux, Online / Web-based, Self-Hosted solutions and SaaS. The best alternative is RackTables, which is both free and Open Source. Other great apps like CMDBuild are i-doit (Free, Open Source), Relinx (Freemium), Docusnap (Paid) and DATAGERRY (Free, Open Source).
Racktables is a nifty and robust solution for datacenter and server room asset management. It helps document hardware assets, network addresses, space in racks, networks configuration and much much more!
Relinx is a flexible tool that can be used as an Asset Management, Inventory Management, Configuration Management Database. Define the model on the fly and validate your data against it. Changes to the model don't affect your data. Import your existing data in CSV format.
A CMDB is a database which includes all informations about objects (i.e. servers, routers, locations, maintenance contracts), that are required for operating an IT infrastructure. Also the relationships between objects are stored (i.e. server a is placed on location b).