There are several considerations, whether we want to implement Oracle Real Application Cluster or not in vSphere environment. These are some simple writings of the Pros and Cons analysis.
|Pros Analysis – Oracle RAC on vSphere||Cons Analysis – Oracle RAC on vSphere|
|Availability perspective: It will create zero downtime of availability (but VMware already has VMware HA features) if customer thinks that the VMware HA feature is good enough (approximately 5 minutes RTO) then no need to consider RAC for availability option.||Cost perspective: customer need to purchase additional licenses for Oracle RAC capabilities for each cores of the servers in the database cluster.|
|Performance perspective: it “might” help the database performance if needed. But, some DBs can have better performance with RAC, some don’t (ex: batch processing intensive application). It depends on the architecture of the application itself (need to be tested).||Manageability perspective: It will create additional complex things to manage (such as oracle clusterware, ASM disks, and additional RAC processes).|
|Recoverability perspective: it will create zero downtime experience, if the failure is happening on the host. But, if the failure is happening on the shared storage connection then recovery process need to be conducted from backup or disaster recovery mechanism.||Resource perspective: customer will need to create min 2 VMs for each DB in different ESXi hosts for full capability of RAC, anti-affinity should be configured so the VMs won’t start in the same host.|
So, basically the decision will be on your hand. Whether you are willing to “pay the price” for the features that you “need”. Ask the question again: do you really need the features?