Let?s say we have two instances, DB2 and TEST. DB2 contains node scan directory with some nodes and TEST is the standalone instance with no directory in it.
1. Now, db2 probe shows that instance in probe GUI which is set in the environmental variables (DB2INSTANCE) and corresponding to that instance, databases list is displayed under Default DB names.
2. For example, If we have ?DB2? instance set in environment variable, then it will be displayed on GUI. Additionally, all nodes in the node scan directory of DB2 instance will be displayed, but the condition is that the node should have atleast 1 database in it.
3. If environment variable points to TEST, then only this instance is displayed on the GUI and since it has no nodes in node scan, no other instances will be displayed.
?DB2 Control centre also works with the same concept.