Virtualizing Exadata machine has become an important deployment decision for many Exadata customers and most of them like to explore or at least discuss virtualization to see if there is any benefit for them. I believe you should have a good use case to virtualize Exadata machine and it should not be your standard install. Keeping that in mind I like to list following use cases where it makes sense to virtualize Exadata machine.
Cost Saving: With the introduction for Elastic configuration and Capacity on Demand (COD), you can already save significant amount of money on licensing and initial investment. With Exadata Elastic configuration option, you can build Exadata with almost any configuration of compute and storage servers. And Capacity on Demand (COD) option allows you but Oracle license in increment. With minimum of 40% must be license, you will be able buy 1/8th rack by only licensing 8 cores per server. So how will OVM with safe money on Licensing? Additional Cost Option Licensing. Virtual machines on Exadata are considered Trusted Partitions and therefore software can be licensed at the virtual machine level instead of the physical processor level. Without Trusted Partitions, database options and other Oracle software must be licensed at a server or cluster level even though all databases running on that server or cluster may not require a particular option. Even with Unlimited License Agreement (ULA) organizations don’t have unlimited licensing for everything (Golden Gate, Advance Security, Advance compression, etc). Some of the licensing options are very expensive and can end up playing key role in your decision to buy Exadata machine.
Compliance: Secondly, I see compliance as another reason to virtualize Exadata Machine. There are different types of compliance requirements HIPPA, PCI DSS and Certifications. We already have a clear definition of HIPPA, PCI DSS compliance requirements and none of them will require you to virtualize Exadata machine. But certification is different, different software and hardware vendors will have set of Software & Hardware requirements to certify their application. You might be required to isolate your workload at database level or cluster level or operating system level. For Example, if your databases contain sensitive client data from different business partners you might be required to isolate data at operating system level or even physical level. You can achieve different level of isolation with Exadata Machine without using OVM. You can have additional Oracle RDBMS Homes to provide Oracle binary files isolation, you can also have different disk groups to provide storage isolation and it is also possible to have a separate physical cluster if you have half or full Exadata rack. But you won’t be able to have two separate physical Oracle Clusters on quarter or eight rack. Using VM’s you will be able to install two or more VM Oracle clusters and achieve operating system level isolation.
Consolidation: Exadata is optimized for both OLAP and OLTP database workloads. Its balanced database server and storage grid infrastructure also makes it an ideal platform for database consolidation. Consolidated environments running on Exadata can use Oracle Virtual Machine (OVM) to deliver a high degree of isolation between workloads. This is a very desirable feature for hosted, shared, service provider, and test/dev environments. Using OVM, multiple software clusters can be deployed on the same Exadata Database Machine, which enables consolidation of applications that have specific clusterware/rdbms/maintenance needs. Not every organization have a separate Exadata machine for development and performance testing. Ideally you should have development and test environments on Exadata machine, so you can take full advantage of Exadata features like smart scan and offloading. You would also like to separate prod, pre-prod and test environments to define separate maintenance windows. For example, if mission critical applications sharing the same Exadata machine with development or test systems, then the frequent changes made in development and test systems will impact the availability and stability of the mission critical applications.
Don’t do it unless you have good use case for it.