Does that means using Availability Group to have it as Active/Active ?No.
appreciate if you can direct me to a document to build this 3 node A/A clusterIf you can build a cluster with 2 nodes then you'll be able to build a 3 nodes cluster. The process is exactly the same just having one more node to be installed and configured.
scom and sccm reporting cannot share an instance of SSRS. so I cannot install scom an sccm reporting on node 3 together.I didn't know that. Do you have any link to a document that says that? If that's true then what you can do is to install 2 MSSQL instances in node 3, one for SCOM SSRS and another one to SCCM SSRS.
SSRS is not cluster awareI'm assuming the cluster is only for databases and not for applications. You should have SCOM, SCCM and SSRS in different servers and more important, not installed in this cluster.
This will considerably increase the number of SQLl enterprise licenses as I need multiple licenses for three active nodes.Depends if you have licensing by CAL or by Processor. Which one do you have?
then if I install SSRS on the sccm and scom servers, additional licenses will be required just to run SSRSI'm not aware of how SSRS license works but I think is similar to SQL Server.
my question is when you have a three node cluster, will I use the default instance on all the three servers or will I be creating named instances.Clustered instances can't be default named. They are always named instances.
I am not very sure about the sql A/A clusterYou'll need to pay licensing in the Passive node anyway, so why let a node completely Passive when it can help your business to have a better performance? Don't forget that in an Active/Passive mode, the Active node need to have double of the resources to keep everything running smoothly. So, double of RAM and CPU.
At the risk of adding yet more confusion and contradictions, what I read stated that the first passive AG group must be licensed but not the second, i.e., 2 licenses not 3 for a primary and two AGs.That's strange because you license MSSQL instances and not AGs. A MSSQL instance can have an AG and not all databases need to be part of an AG.
For example:
Node 1 - SCCM database; WSUS
Node 2 - SCOM Op; SCOM DW
Node 3 - Reporting (SCOM & SCCM); AV