Q. What type of historical PI information would not be available after a PI repository change?
A. The original history data of the migrated DBSS agents as stored in FMS Repository would be available after DB agents migration. The PI specific data would be lost, if the Repository is changed for migrated agents. This means you would lose Top SQL, Change Tracking, Blocking Locks history.
Since some portion of PI data such as Instance level statistics is preserved in FMS Repository, you would be able to see history data for Wait Events and Reads & Writes (both Logical & Physical).
Q. What data in FMS Repository is preserved when a DBSS agent is migrated to a new FglAM.
A. Everything. The history data of a DB agent in the FMS Repository is not touched during agent migration. Hence all agent history data in FMS Repository would remain intact.
If you remove the database agent recreate from scratch on a new FglAM, then all of the above would be lost.
Q.Instead of migrating a DB agent, can a user simply delete the agent from FMS UI and re-install the same DB agent on the new FGLAM host?
A. This is not the recommended way but it will work. When a user re-installs a DB agent on a new FglAM host, though the DB agent name may be the same, its agent_id is coming from a new FglAM (with a new UUID) and thus it will be treated as a new agent by FMS.
Although the agent topology will be new, the cluster/instance topology will remain and the data will continue to be submitted on the same location (assuming the monitored host and the instance name have not changed in the newly created agent). The only data that will be lost is the data kept in the agent topology, and that is mainly the usability metrics.
Q. When migrating DB agents from one FglAM to another, a user wants to keep the PI Top SQL metrics and Blocking History.
A. Scenario-1: The target FglAM already has agents that are configured to a different PI repository.
In this case, the migrated agents cannot keep ANY of the PI data as the migrated DB agents would need to be re-assigned to a new Repository.
Scenario-2: The target FglAM has no agent that is configured to PI or has agent that are configured to the same PI repository
In this case the migration will move the DB agent to the new location and the PI history will remain untouched