Not really a question per se, more asking an opinion or to form a discussion.
The big push from SAP is to consolidate lots of different SAP systems into a central S/4 HANA system.
From an admin, functional point of view that sounds all rather good and prevents system sprawl as we had with
traditional databases, but it assumes Moor's law still holds up and infrastructure/Cloud costs are linear and can scale forever.
However Moore's law is slowing down with likely only a few more processor shrinks possible, with intel having some extensive delays in their new process.
So what does this mean.
Spreading smaller systems over multiple small machines actually end up cheaper than going for one large machine.
e.g. a 4 Socket server is not twice the price of a 2 socket server more like 2.5 times the price, Going from 4 to 8 Sockets can mean up to 4 times the price for a doubling of capacity, beyond that and you are in propriety hardware class with only two vendors, HP/SGI and Bull.
So what about scale out?
From my experience customers do not like to scale-out on BW and you can only scale OLTP workloads out in 12TB instance sizes which means an 8 Socket server. (An area SAP really needs to work on, the ability to scale-out with much smaller instances).
So to answer my own question.
Only consolidate systems where you can comfortably fit into a 2 socket or 4 socket system. So you are talking 3TB or 6TB for OLTP and 1.5 and 3TB for OLAP.
Obviously business requirements may take precedent, but being on the bleeding edge of technology is not always a good idea, especially when the rate of technology change is slowing down.