Are pluggable DBs a substitute for dedicated VMs (DB servers) ?
DB version: 12.2 , 12.1
Platform: Oracle Linux, RHEL 7.X
I have never worked on 12C, so I have no idea on the rationale behind Pluggable DBs. Are pluggable DBs a substitute for dedicated VMs (DB servers) ? ie. Are pluggable DBs are substitute for Option2 shown below.
I mean, If I have a large physical server with 252 GB RAM and 80 CPUs and I want host 5 databases in this server. I have 3 options as shown below
Option1
Install the OS in the physical server and create 5 individual DBs in it. But, this would mean I am wasting physical memory (RAM) and CPU for each instance's mandatory processes (smon, pmon, lgwr, dbwr ...)
Option2.
I can create 5 VMs (using OVM or VMWare) and create the DBs in the each of these VMs. But, this would mean I am wasting physical memory (RAM) and CPU for each instance's mandatory processes (smon, pmon, lgwr, dbwr ...) in each VM.
Option3 (using 12c Pluggable DB feature)
Using 12C pluggable DB feature, I could create just have one container database in this physical server and create multiple pluggable databases within this container database. If I am not mistaken, there is only one set of mandatory processes (smon, pmon, lgwr, dbwr ...) for a container database in a Pluggable DB environment. ie. No dedicated mandatory processes (smon, pmon, lgwr, dbwr ...) for each pluggable database.
Are my above assumptions right ?