I've searched the Oracle site and even though there are a number of white papers, I haven't seen anything like the old 9i sizing guide. I'll certainly appreciate any info on this. Thanks in advance.
Rather, the system resources are dictated by usage patterns. I've had 10TB databases that used less CPU than 100GB database. It all depends on how that data is getting used. The best way to size the server is to analyze the usage patterns on an existing server. Does your buffer cache need more memory to support the application with this data? Are your CPUs getting maxed out? I typically use existing knowledge to guide future hardware procurements. In the absence of existing knowledge, I have always used estimates based on what I think is going to happen with the data. Other than sizing my storage, I rarely take the overall data volume into account.