|Oracle® Enterprise Manager Cloud Control Upgrade Guide
12c Release 1 (18.104.22.168)
This chapter describes the following:
Deferred Data Migration is a post-upgrade activity to migrate the format of the data stored in an earlier release of Enterprise Manager to the format compatible with the upgraded Enterprise Manager system. The migration activity is essentially a job in Enterprise Manager that is submitted when the Oracle Management Repository gets upgraded and is scheduled to run in the background when the upgraded Enterprise Manager system starts functioning.
The format of the data stored in Enterprise Manager Cloud Control is different from the format in which the data was stored in any earlier release of Enterprise Manager.
When you upgrade from an earlier release of Enterprise Manager to Enterprise Manager Cloud Control, the data format gets automatically converted or migrated to the format that is compatible with Enterprise Manager Cloud Control.
However, the time taken to migrate the data format depends on the volume of data available in your earlier release of Enterprise Manager. Therefore, if you have a large amount of data, then it takes longer to migrate, and as a result, the upgrade process takes more time to complete. Unfortunately, until the upgrade process completes, your existing Enterprise Manager system might be unavailable, particularly when you use a 1-System upgrade approach (either on the local host or on a different, remote host).
Considering this, Oracle has fine-tuned its upgrade process to migrate the data format in two distinct phases.
In the first phase, when the Enterprise Manager system is shut down and upgraded, the most critical data relevant to the functioning of Enterprise Manager Cloud Control is migrated within a short time so that the new system can start functioning without much downtime. At this point, only some historical data is unavailable, but you can start monitoring the targets in the upgraded Enterprise Manager system, and see new alerts generated by the upgraded Oracle Management Agent.
In the second phase, after the upgraded Enterprise Manager system starts functioning, the remaining data is migrated.
The data whose format is migrated in the second phase, after Enterprise Manager Cloud Control starts functioning, is called the Deferred Data, and this process of migrating from old to new format is called the Deferred Data Migration.
To track the status of deferred data migration jobs, follow these steps:
In Cloud Control, from the Setup menu, click Post Upgrade Tasks.
On the Post Upgrade Tasks page, click the Deferred Data Migration tab.
The tab provides a list of data migration jobs with their status, start date and time, and end date and time.
In this tab, you can do the following:
To start a data migration job for a component, select that component and click Start. By default, the job starts immediately. You cannot change this behavior.
To rerun a failed job, click the status icon to reach the Job Run page. On the Job Run page, click Edit. On the Edit <JobName> Job page, click Submit to rerun the job.
To hide or unhide the table columns, from the View list, select an appropriate option.
To detach the table from the screen, click Detach.