Our company has 5 different databases. None of the multiple databases relate or utilize cross database joins. We have ample resourcing and budget.
Our company is debating between:
5 databases on 1 server instance,
or 5 databases on 5 different servers.
Question: What are some specific problems, obstacle issues which can occur, if we place everything on 1 single server? My background is not DBA, so would like to learn examples I can discuss with team.
The argument for 1 server instance at company: We have "Resource governor" and "AlwaysOn Availability Groups" with Failover clustering. Resource governor will handle Memory, Cpu, io workloads between databases. So along with AlwaysOn DR, it can handle runaway queries, bad design, memory issues.
Databases are 100GB each, critical company information, 50 million rows minimum
We process 300 transactions/sec
RTO = 10 min