The most important factor in determining sizing for AppDynamics Controller is the projected metric load per minute on the Controller. This is because the metric load represents the actual workload on the Controller, which depends on the nature of the application, the AppDynamics configuration, and the usage patterns. The number of agents, the type of agents, the number of administrators/end users, and the number of AppDynamics applications are only rough estimates that can vary greatly depending on the specific scenario. Therefore, it is recommended to test the performance of the system in a staging environment and verify the Controller sizing using the metric upload rate before deploying to production.Reference:Controller System Requirements,Performance and Controller sizing guidelines,How to Run AppDynamics in Microsoft Azure,Platform Requirements

The Health Rule REST API allows you to create, configure, update, and delete health rules for multiple applications simultaneously. To use this API, you need to specify the application in the URL string. You can use either the application ID or the application name for this purpose. The application ID is a unique numeric identifier for each application in the Controller. The application name is the display name of the application in the AppDynamics UI. You cannot use the application alias, GUID, or REGEX for the Health Rule REST API.Reference:Health Rule APIandRetrieve All Business Applicationsin the AppDynamics documentation.

To set up AppDynamics Controllers as a high availability pair, you need to meet the following requirements1:

Passwordless SSH must be configured between the two Controller servers. This allows the Enterprise Console to automate the configuration and administration tasks associated with a highly available deployment on Linux systems.

Both servers must have the Controller software installed prior to setting up high availability. The Controllers in an HA pair must be equivalent versions, and be in the same data center.

Both servers must have identical directory structures for the Controller installation. The individual machines in the Controller HA pair need to have an equivalent amount of disk space.Reference:Prerequisites for High Availability

According to the Cisco AppDynamics Professional Implementer (CAPI) documents, when updating the Database Agent, you need to follow these steps12:

Stop the agent as described for your specific installation in Start and Stop the Database Agent.

Make a copy of the existing agent directory, <db_agent_home>. Backing up allows you to revert to the previous agent installation if you need to. You can also copy over the controller-info.xml configuration file to the new installation to ensure the agent configuration is maintained.

Install the Database Agent as described for your specific installation in Administer the Database Agent.

Copy the <backup_db_agent_home>\conf\controller-info.xml file to the new installation directory, <db_agent_home>\conf. To ensure the agent configuration is maintained, copy the <backup_db_agent_home>\conf\controller-info.xml file to the new installation directory, <db_agent_home>\conf.

Start the new agent. See Start and Stop the Database Agent.

Verify the Database Agent Installation. See Verify the Database Agent Installation.

Therefore, the correct statements are:

The Database Agent must be stopped and restarted during the upgrade. (A)

Controller-info.xml is the only file that needs to be migrated from the previous agent to the new agent. (D)

The incorrect statements are:

If the agent is moved to a new location during the upgrade, the AppDynamics Controller must be reconfigured to reference the new location of the agent. (B) This is not true because the controller-info.xml file contains the information about the Controller host, port, account name, access key, and SSL settings. As long as this file is copied to the new agent location, the Controller does not need to be reconfigured.

All data collectors created from the previous agent must be migrated to the new agent. This is not true because the data collectors are configured on the Controller UI, not on the agent. The agent collects the metrics from the databases and sends them to the Controller. The data collectors do not need to be migrated to the new agent.

After the Database Agent is upgraded, the AppDynamics Controller must be restarted. (E) This is not true because the Controller does not depend on the agent version. The agent and the Controller are compatible as long as they meet the Agent and Controller Compatibility requirements.

1: Upgrade the Database Agent - AppDynamics

2: Release Upgrade Checklist for Database Agents - AppDynamics

The AppDynamics Controller Admin Console lets you configure certain global settings for the Controller, such as metric retention periods, UI notification triggers, tenancy mode, and accounts in multi-tenancy mode1. Two of the settings that an administrator can configure from the AppDynamics Controller Admin Console are:

License allocation: This setting allows you to view and manage the license usage and availability for your Controller. You can see the total number of licenses, the number of licenses in use, the number of licenses available, and the license expiration date for each agent type.You can also allocate licenses to specific applications or accounts, and set license limits and alerts2.

Retention periods: This setting allows you to specify how long the Controller retains the metric data and the event data for your monitored applications. You can configure the retention periods for different types of data, such as minute-level metrics, hour-level metrics, day-level metrics, transaction snapshots, and events.You can also configure the data purge schedule and the data backup schedule3.