To CAS or not to CAS, That is the Question

Hi everyone, my blog output has been down a bit recently, the past few weeks have been really busy which has meant I haven’t had time to post anything. For many administrators and consultants alike we have had the RTM of Configuration Manager 2012 available for some time now. The differences between the current version and Configuration Manager 2007 are numerous over many different aspects of the application. One of these changes is the central site which is now a central administration site or a CAS.

When you designed in Configuration Manager 2007 we often needed a central site to manage our primary sites for a number of design based reasons, a couple of them are…

  • Split administration of server and client estates
  • Separation of permissions
  • Internal politics
  • Management of bandwidth in slow sites

When you roll forward to Configuration Manager 2012 all of these reasons have been removed, so that begs the question, why would you ever install a CAS?

Hierarchy Size

A stand-alone primary site can support up to 100,000 clients, so the most obvious example here is if you need to manage 110,000 clients (basically anything over 100,000 clients) then you will need a CAS to manage your primary sites which will replicate with your CAS.

Any Others?

Technically no. From a technical point you now have no reason for that CAS. Granted you might still have internal politics but the great new features such as role-based administration, security scopes and bandwidth management on the distribution point and with BranchCache have removed these previous technical obstacles, which make the design much easier.

Not forgetting how much easier it is to install a secondary site with SQL Express rather than the full installation.

Uh Oh! I implemented a CAS

I reviewed a design the other day where it was recommended the customer implemented a CAS with only 5,000 clients in scope for management.

If you have done a similar thing then don’t panic. While it’s not a recommended approach you won’t have any operational issues. It is just important that you note the extra administration overhead of administering another server, another Windows license and then potentially have to troubleshoot replication issues between primary sites and your CAS.


So in summary, unless you have a potentially large hierarchy then why implement a CAS? From a technical point of view you have no real reason to. If internal politics are still a concern which may lead you down this route, try to resolve this issues, explain why a flat hierarchy would be better for you.


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About Martyn

Martyn is one of the Senior Cloud Architects and DevOps Team Leader at one of the worlds leading Cloud Transformation Specialists Inframon. Martyn is responsible for the architecture of some of the largest Azure deployments in EMEA and is a advisor to a many businesses on their strategies. Martyn is a regular speaker at Microsoft events and community events on Azure and DevOps, giving his insight to a growing number of audiences.

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