If you’re looking for a guide for upgrading your SCCM 2012 SP1 environment to R2. I recommend you to use Johan Arwidmarks: “A Geeks Guide for upgrading to ConfigMgr 2012 R2 and MDT 2013”. Great guide with useful Insights from the deployment master himself.
If you have a CAS, remember this: Start the process on the CAS and work your way down the hierarchy.
NB! (Recent experience)
After you have updated your CAS it needs to re-establish its site links. Expect some heavy replication.
You will get an error related to “Parent site replication status” on all primary sites. Wait until the site links are back up and running before you upgrade your primary sites (prereq check will stop you). In my experience, this can take 1-2 hours. Pay attention to CPU/Disk activity before proceeding with the upgrade.
Objreplmgr.log and replmgr.log is good logs to check out.
High Level steps:
- Test the site database for upgrade
- Uninstall ADK 8.0
- Install ADK 8.1 (make sure to download the re-release, available on October 17, 2013)
- Install ConfigMgr 2012 R2
- Install MDT 2013
- Post configuration (fix a few things like creating new boot images, new sequences, and possible fix network access account and PXE)
Read Johan’s blogpost here
NB! Additional resources.