As Munender Singh and robertgreen mentioned the Identification rules are used by Discovery to determine whether to update an existing CI or create a new CI. To access the Identifiers enter "Identifiers" in the Navigation pane. In London there are over 400 Identifiers. The Hardware Rule Identifier is shown.
For some of the more common discovered CIs, the Hardware Rule Identifier rule is used for Identification. The rule applies to the Hardware [cmdb_ci_hardware] table as well as child tables off the Hardware class. For example, Windows Server [cmdb_ci_win_server] and UNIX Server [cmdb_ci_unix_server] tables are child tables off the Hardware table and the Hardware Identifier rule applies to these 2 tables.
On the Hardware Rule Identifier form, the Identifier Entries tab contains 4 active records. Each active record contains different Criterion attributes. Criterion attributes are used for coalescing/identification and are applied in Priority order as shown.
For example, when discovering a Windows Host the Hardware Rule Identifier is used to determine if the CI needs to be updated or create a new CI. During identification, the 1st Identifier Entry (Priority 100) attempts to match on the serial_number and serial_number_type Criterion attribute. If a match isn't found in the CMDB, then the next Identifier Entry is attempted. The 2nd Identifier Entry (Priority 200) attempts to match on the serial_number Criterion attribute. If a match isn’t found in the CMDB, then the next Identifier Entry is attempted. The 3rd Identifier Entry (Priority 300) attempts to match on the name Criterion attribute in the CMDB. If a match on name is found, no other Identifier Entries are attempted and discovery updates the CI in the CMDB.
To troubleshoot Identification issues during discovery, the Discovery Log will contain more information. As an example, the following discovery log entry found a match on the 1st Identifier Entry.
