RAC Installation Requirements

Question

Hi Gurus
We would be thinking to install RAC for new application.
My requiremets are as follow.
These are all general requirements and no specific to OS and any thing
1> What could be the Hardware requirements (Like Nodes should be same hardware or change can also possible in RAC)
2>Software requiremets (Like what all softwares are required for installing RAC,Any software depedency)
3>Network requirement
and last one
Can i have different node in RAC as 1 node running in London and other in New York ?
Thanks in Advance !!!!!!
Regards

Answer 1

You should be able to find most of your answers in the "Oracle® Real Application Clusters
Installation Guide" - for 11g R2, that document can be found here. See Chapter 1 Section 2, "Overview of Server Hardware, Network and Operating System."
Although not required, ideally you would want the hardware configuration of each node to be identical. However, it is entirely acceptable for the hardware configuration of each node in the cluster to be configured differently (different number of CPUs, physical memory, etc.). Oracle recommends that the Operating System release/version/patch level be the same on all nodes in the cluster.
As for your question regarding the distance between nodes in a cluster, there is the concept of a "[Stretch Cluster|http://www.google.com/search?source=ig&hl=en&rlz=&q=oracle+stretch+cluster&aq=f&oq=&aqi=g1]," whereby nodes in a cluster can be placed up to a finite distance apart from one another to prevent situations where the loss of a data center takes out both/all nodes. The distance between London and New York likely exceeds the limitation for a stretch cluster, though. You could perhaps consider having two clusters: One in New York and one in London and having Data Guard set up between them. ;-)
HTH
-RT