System Landscapes and System Data 
To model your business processes, you use various SAP applications (e.g. SAP CRM, SAP ERP, SAP PLM). You enter the existing system landscape in the Landscape Management Database (LMDB). This data helps you to maintain and enhance the landscape consistently.
For more information about managing the system landscape, see Create Product System Information.
System Data for Product Maintenance with the Maintenance Optimizer
The Maintenance Optimizer gets its system data from the Landscape Management Database (LMDB). In maintenance transactions, it takes the product version specified for the product system, and the relevant and additionally installed product instances, into account. It also handles the landscape patterns into which you have classified the technical systems.
The sources of the system data in the system landscape can be configured, and depend, for example, on the system type. To get Java technical system information in the SAP Solution Manager, you must connect to the System Landscape Directory (SLD). Data from ABAP systems can be read from the local TMS domain server via RFC connections. An SLD connection is strongly recommended. Other system types are connected to SLD via the available data suppliers.
The Maintenance Optimizer can only calculate meaningful configuration files if the system data in the Landscape Management Database is consistent. Use the verfication function in the Product System Editor. For more information, see Perform Verification Checks.
More Information
For more information about the System Landscape Directory (SLD), see the System Landscape Directory Planning Guide in the SAP Community Network, unter http://scn.sap.com/docs/DOC-8042.