What Is a Virtual Machine?
Wikipedia defines a virtual machine
as “a simulation of a machine (abstract or real) that is usually different from
the target machine (where it is being simulated on).” In essence, it is a fully
functioning software version of an operating system/host that acts as its own
independent host, sometimes referred to as a “guest.” It is possible and common
to house many guests on one physical host. Virtual machines can run an
operating system on non-standard chipset—for example, running windows on a Unix
box, and vice versa.
In many cases, organizations have a
virtual machine “farm,” which is a collection of physical servers connected to
a common shared disk. In this scenario, any guest can be running on any given
physical machine in the farm. In most modern virtualization implementation,
high availability is maintained if a physical machine goes down because a
remaining healthy physical machine in the farm can detect that, assume
ownership of the guest, and boot it up.
But is it Supported by Oracle?
The phrase that Oracle uses is
“supported, but not certified.” This means that Oracle has not certified EPM
System products on third-party virtualized environments; however, Oracle
Support will assist customers who are running EPM System products on third-party
virtualized environments. The supportability matrix can be found here:
http://www.oracle.com/technetwork/middleware/bi-foundation/hyperion-supported-platforms-085957.html
- When a customer logs a previously unreported issue, Oracle Support might require the issue to be diagnosed in a non-virtualized environment when there is reason to believe that the virtual environment is a contributing factor. Oracle Support might refer customers to the third party virtualization vendor for issues that cannot be duplicated in non-virtualized environments.
- When a problem has been previously reported and a resolution is available, Oracle Support may recommend the appropriate solution on the non-virtualized operating system. If that solution does not work in the virtual environment, the customer will be referred to their virtualization software vendor for support. If the customer demonstrates that the Oracle solution does not work when running on a non-virtualized operating system, Oracle will resume support, including logging a bug with Oracle Development for investigation if necessary.
- Oracle will support virtual environments using Oracle VM.
Specifically, Oracle has not
certified ANY of its products for use on third-party virtualization
technologies, such as VMWare, and can reserve the right to direct your support
case to the virtualization vendor if they so determine (see Oracle Knowledge
Base article ID 249212.1). However, Oracle will support you in a virtual
environment if you are using OracleVM as your virtualization technology.
The Good and the Bad
Probably the biggest reason why
virtualization is so attractive is for pure server consolidation—running more
hosts on fewer servers. Instead of dedicating an entire physical server to one
operating system deployment, people can do more to better utilize the
resources. Also, virtualization allows users to dynamically allocate resources,
so adding/removing memory, CPU, or disk resources to a guest is a snap.
Minimizing physical servers nets an obvious cost and time savings. In essence,
virtualization allows IT organizations to maximize their hardware performance
and minimize IT maintenance.
Another major advantage is the ease
of backup/recovery and disaster recovery. Backing up a host can be as easy as
getting a snapshot in time. And given that guest images are portable, they can
be shipped to anywhere and run on another server, such as a disaster recovery
data center. Of course, backup and disaster recovery is possible and common on
physical machines; however, virtualization makes it easier and standard across
the enterprise.
People will tell you the main
disadvantages of virtual machines is performance. While there is an overhead of
having two operating systems (the physical host and the guest running on it),
the amount of degradation differs and is debatable.
Is it Right for You?
The industry is seeing more and more
use of virtualization in EPM deployments. But is it right for you? The short
answer is, “It depends.” Many factors influence your decision to consider a
virtual environment.
- Current hardware, SAN landscape, and maturity of existing virtualization technology
- Performance needs
- Current backup/recovery and high availability technology abilities
- Disaster recovery needs
- Tolerance to downtime and data loss
- What products you have (Virtualization decisions may be different with Planning, Reporting, Financial Management, or Essbase)
- Data center space, power options
- DEV, TEST, or production instances
- Oracle Support policy
- Internal support capabilities
While EPM products are expected to
function properly in virtual environments, there might be performance
implications, which can invalidate Oracle's typical sizing recommendations. An
analysis should be performed within the context of the specific application
being hosted in the virtual environment to mitigate potential resource
contention, as this can result in degradation of performance and scalability,
particularly under peak load. In short, only a detailed hardware design and
full understanding of all the factors can say for sure.
