A source hierarchy is a Configuration Manager hierarchy that contains data that you want to migrate. When you configure migration and specify a source hierarchy, you specify the top-level site of the source hierarchy. This site is also called a source site. Additional sites that you can migrate data from in the source hierarchy are also called source sites. When you configure a migration job to migrate data from a Configuration Manager 2007 source hierarchy, you configure it to migrate data from one or more specific source sites in the source hierarchy. When you configure a migration job to migrate data from a System Center 2012 Configuration Manager or System Center 2012 R2 Configuration Manager source hierarchy, you only need to specify the top-level site.

You can configure only one source hierarchy at a time. If you configure a new source hierarchy, that hierarchy automatically becomes the current source hierarchy replacing the previous source hierarchy. When you configure a source hierarchy you must specify the top-level site of the source hierarchy specify credentials for Configuration Manager to use to connect to the SMS Provider and site database of that source site. Configuration Manager uses these credentials to run data gathering to retrieve information about the objects and distribution points from the source site. As part of the data gathering process, child sites in the source hierarchy are identified. If the source hierarchy is a Configuration Manager 2007 hierarchy, you can then configure those additional sites as source sites, with separate credentials for each source site.

Although you can configure multiple source hierarchies in succession, migration is active for only one source hierarchy at a time. If you configure an additional source hierarchy before you complete migration from the current source hierarchy, Configuration Manager cancels any active migration jobs and postpones any scheduled migration jobs for the current source hierarchy. The newly configured source hierarchy then becomes the current source hierarchy. You can then configure connection credentials, additional source sites, and migration jobs for the new source hierarchy. The original source hierarchy is now inactive.

If you restore an inactive source hierarchy, and you have not previously used the Cleanup Migration Data action, you can view the previously configured migration jobs for that source hierarchy. However, before you can continue migration from that hierarchy, you must reconfigure the credentials to connect to applicable source sites in the hierarchy, and then reschedule any migration jobs that did not finish.

Caution
If you migrate data from more than a single source hierarchy, each additional source hierarchy must contain a unique set of site codes.

For more information about configuring a source hierarchy, see the Configuring a Source Hierarchy for Migration section of the Configuring Source Hierarchies and Source Sites for Migration to System Center 2012 Configuration Manager topic.

Source sites are the sites in the source hierarchy that have the data that you want to migrate. The top-level site of the source hierarchy is always the first source site. When migration collects data from the first source site of a new source hierarchy, it discovers information about additional sites in that hierarchy.

After data gathering completes for the initial source site, the actions you take next depend on the product version of the source hierarchy.

Configuration Manager 2007 SP2 Source Sites

After data is gathered from the initial source site of the Configuration Manager 2007 SP2 hierarchy, you do not have to configure additional source sites before you create migration jobs. However, before you can migrate data from additional sites, you must configure additional sites as source sites, and Configuration Manager must successfully gather data from those sites.

To gather data from additional sites, you individually configure each site as a source site. This requires you to specify the credentials for Configuration Manager to connect to the SMS Provider and site database of each site. After you configure the credentials for a source site, the data gathering process for that site begins.

When you configure additional source sites in a Configuration Manager 2007 SP2 source hierarchy, you must configure source sites from the top down, which means you configure the bottom-tier sites last. You can configure source sites in a branch of the hierarchy at any time, but you must configure a site as a source site before you configure any of its child sites as source sites.

Note
Only primary sites in a Configuration Manager 2007 SP2 hierarchy are supported for migration.

System Center 2012 Configuration Manager SP1 and System Center 2012 R2 Configuration Manager Source Sites

Immediately after you specify a source hierarchy, configure credentials for each additional source site in a source hierarchy, or share the distribution points for a source site, Configuration Manager starts to gather data from the source site.

The data gathering process then repeats itself on a simple schedule to maintain synchronization with any changes to data in the source site. By default, the process repeats every four hours. You can modify the schedule for this cycle by editing the Properties of the source site. The initial data gathering process must review all objects in the Configuration Manager database and can take time to finish. Subsequent data gathering processes identify only changes to the data and require less time to finish.

To gather data, the top-level site in the destination hierarchy connects to the SMS Provider and the site database of the source site to retrieve a list of objects and distribution points. These connections use the source site access accounts. For information about required configurations for gathering data, see Prerequisites for Migration in System Center 2012 Configuration Manager.

You can start and stop the data gathering process by using the Gather Data Now, and Stop Gathering Data actions in the Configuration Manager console.

After you use the Stop Gathering Data option for a source site for any reason, you must reconfigure credentials for the site before you can gather data from that site again. Until you reconfigure the source site, Configuration Manager cannot identify new objects or changes to previously migrated objects at that site.

Note
Before you expand a stand-alone primary site into a hierarchy with a central administration site, you must stop all Data Gathering. You can reconfigure Data Gathering after the site expansion completes.

Gather Data Now

Stop Gathering Data

Concepts