Does DISCOVER_DB affect DB2 agent monitoring? (4377783)

In the DB2 Hardening Guide for DB2 LUW … there are 3 parameters that are not set ( and default to ENABLE) but are being flagged and the value should be set to DISABLE.

Would the DB2 agent be impacted if the DISCOVER_parameters are set to DISABLE

• DISCOVER
• DISCOVER_INST 
• DISCOVER_DB 

In IBM DB2, the parameters DISCOVER_INST and DISCOVER_DB are related to the process of discovering instances and databases in a DB2 environment, primarily for administrative and monitoring purposes. These parameters control how DB2 handles the discovery of databases and instances when executing commands and queries.

The DISCOVER parameter is related to enabling or disabling the automatic discovery of databases or instances on a DB2 server. It may be used in configurations or commands that involve automatic detection of DB2 databases or instances on the system.

• Purpose: It controls whether DB2 automatically discovers databases and instances for use in certain tools or commands, or if the user must manually specify them.
• Use case: Typically, enabling or disabling this parameter impacts administrative tasks and tools that query DB2 for available instances or databases.

The DISCOVER_INST parameter controls whether DB2 automatically discovers all the instances on the machine.

• Purpose: When enabled, DB2 will automatically detect and display all instances on the system. This is particularly useful when you want DB2 commands or tools to be aware of all DB2 instances running on a machine without manually specifying each one.

• Use case: In environments with multiple DB2 instances, enabling DISCOVER_INST allows tools and commands to automatically detect and work with any instance present.

  Example:

  • When enabled, you can run commands like db2 list instance and it will return a list of all instances on the server.

The DISCOVER_DB parameter controls whether DB2 will automatically discover and list all databases within a DB2 instance.

• Purpose: When enabled, DB2 will automatically detect and display all databases within an instance. This can be useful for administrators or tools that need to be aware of all available databases for monitoring or management purposes.

• Use case: This is helpful when you want DB2 to auto-discover all databases in a given instance without manually specifying each database name.

  Example:

  • If DISCOVER_DB is enabled, running commands like db2 list db directory may return a list of all databases in the current DB2 instance.

If these parameters are disabled, DB2 may not automatically detect databases, and administrators may need to manually reference them when performing tasks.

Note: DB2 Instances are not discovered but are instead manually entered into the DB2 installer window or Agent Status Properties panel when the agent is being created.

The DB2 agent installer (and verifying connections) does use the DB2 command db2 list database directory which is affected by the status of DISCOVER_DB. 

To fully account for the databases that are not discovered by the DB2 agent, users should can add database names into the appropriate popup by clicking the Edit button in the monitored databases row within the DB2 agent status properties page.

Note: The DB2 agent also uses the db2 list active databases global command. Disabling DISCOVER_DB does not directly impact the behavior of db2 list active databases global. The reason is that this command is designed to list active databases across all instances, and it doesn't rely on the local cataloging of databases in the same way db2 list db directory does.

• It will still list all active databases globally, even if DISCOVER_DB is disabled. However, the command will only display databases that are actively connected or being used across all DB2 instances, regardless of whether they are cataloged locally or not.