Database Reference
In-Depth Information
Chapter 4
Supporting Software
After introducing new trends in hardware in Chapter 3, you can read more on how to exploit these with appropriate
software. Choosing the operating environment for the next generation hosting platform is equal in importance to
choosing the hardware. Hardware and software should be certified both from the vendors and in-house. Strong
support contracts with defined Service Level Agreements must be put into place to allow the quick turnaround of
troubleshooting problems.
You should not underestimate the amount of testing it takes to certify an Oracle stack, even if it is primarily for the
database! This certification requires joint efforts by the storage, operating system, and database engineering teams.
Effective management of this joint team effort is important to the overall success. This sounds too logical to be added
to this introductory section of the chapter, but experience shows that a strict separation of duties, as seen in many
large organizations, requires re-learning how to work together.
Enabling Software Solutions
After spending time on evaluating the hardware for the consolidation project, the next step is to think about
deployment of the Oracle 12c database. In the author's opinion, there are two different approaches, depending on the
importance of the environment. These approaches are virtualization and clustering. They both are centered on the
magic terms “high availability” and “disaster recovery.” Clustering can be further broken down, resulting in:
•
Virtualization-based solutions
•
Using active/passive clusters
•
Using active/active clusters
What shouldn't be hidden from the discussion is the fact that complexity and cost increase in almost the same
way as the protection from failure!
High Availability Considerations
The “high availability” baseline is a single instance Oracle database. The following discussion assumes there are no
unnecessary single points of failure in the chosen hardware, which can potentially render the whole solution very
vulnerable. If you want high availability, then you should know it will come at a cost.
Using virtualization-based solutions usually involves a single instance Oracle database installation in a virtual
machine. The physical location of a virtual machine is often irrelevant, and, rather than mapping a virtual machine to
a host, the mapping is on a logical grouping of hosts. Oracle VM Manager calls such a logical group of servers a server
pool. Other vendors use different terminology but the same principle. In case a host has an unrecoverable failure
and must reboot, it is possible to migrate virtual machines from the failed host to another host in the cluster, capacity
permitting. However, there does not have to be a failure: (live) migration of virtual machines is applicable for planned
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