Also, you can follow this video which explain each step for migration of WSUS with all approved updates.
Step by step procedure for migrating WSUS from server W2K3 to W2K12:
Migrate WSUS update
- Stopped WSUS service and synchronization schedule on W2K3 server.
- Installed WSUS role on the W2K12 server. Leave the configuration wizard at the end of installation of role.
- Then created a NT Backup task to the entire WSUS Backup content folder.
- Copy the NT Backup binaries from a W2k3 server and copied it to the W2K12 server.
Migrate WSUS security groups
No need to do anything specific in this step if all the users, groups and security permissions are exact same in new setup. for double you can refer to article described here.
Back up the WSUS database
This is the most important step. You also can see how to do it here. Remember you need to install SQL Server 2012 Management Studio in your W2K12 server as 2005 version is not supported in 2012. This is required for WSUS database import.
- After completing the WSUS database migration, open up WSUS console in the W2K12 server. You may notice that approved updates along with rest updates are there.
- Configure the new WSUS server with exact same configuration (products, classifications, automatic approvals, sync schedule etc… ).
- In group policy of WSUS. Change the host name to the new one.
- Start a manual synchronization in the new server. Once it is finished make sure that the sync is Succeeded.
- As you have change the WSUS server in the domain group policy, you may need to log off and log in to client computers or run a gpupdate /force. Alternatively follow the step in the TechNet article to manually detect a client computer.