So what is a CAS? A CAS, or Central Administration Site, is the name for the site server role in System Center Configuration Manager 2012. What does it do? It’s kind of like a Central Site in SCCM 2007 in the fact that it sits at the top of your sccm hierarchy except it has no ability to manage clients and doesn’t actually process any data it gets from clients. If you’ve worked with a reporting only central site then you’ll have a good idea of what they were attempting to achieve with this model.
Since SCCM 2012 primary site servers now are peers and cannot be tiered, the CAS is used to sit at the top of the pile, take in data processed and managed by the primary servers and give a central point of administration. It’s exactly like the name implies! You can use roles to restrict what certain logged in users see to define the scope of authority on certain individuals. Cool right?
So am I telling you to use a CAS?
Hold on a second here. Let’s explore why you WOULD need a CAS:
- You have the need for multiple primary sites for reasons such as sub branches in the company or delegation due to location
- You have more than 100 thousand clients which is more than the amount of clients a primary can officially support
- You want to distribute load or create resilience on your network
- Basically at any point you require more than one primary!
Remember, the CAS is the only place where you can see ALL the data your SCCM infrastructure creates as all primary sites will pass their data up the chain.
So I am telling you to use a CAS!?
Woah woah…hold your horses! I would actually be inclined to tell you to NOT to use a CAS for a large proportion of scenarios. Only those who have large organizational span or infrastructure across political or geographical areas will need a CAS. For most of us, just using a primary will do.
There used to be, or technically still is at time of writing, a caveat by installing just a Primary site server. You could not join existing primary site servers to newly installed CAS servers! This is all set to change with the advent of SP1 for SCCM 2012.
So why just a primary? What are the reasons for NOT using a CAS?
Simple. Simplicity. If you do not have a CAS or do not have the requirement for a CAS as covered earlier, then your management infrastructure will be that much easier to administrate. You’ll only have one server to manage. That means one instance of SQL. One point of troubleshooting. One place that all the clients will point to and be managed by.
Since SP1 had been announced, if we ever decide to expand our infrastructure or wish to create resilience we can do so by creating a CAS later in the process. It’s not a one or the other type deal with SP1 which is pretty awesome.