Database Reference
In-Depth Information
Virtualization on the ODA creates some unique challenges in installation, as well as the configuration of the device.
The default setup on the ODA is bare metal, which means all hardware has a one-to-one affinity to each component.
In order to convert a running ODA to a virtualized model, a complete reinstall of the appliance has to happen. This is
particularly important to note as an install decision, because data loss or an outage is required for conversion.
Installation of a Virtualized ODA
The default condition of an ODA that is shipped from the factory is the bare-metal state. The process of an ODA
bare-metal installation is explained in detail in Chapter 2. This section will highlight some specific changes, as well
the changes in the ODA offline configurator to handle virtualization.
Preparation for Virtualization
Virtualization on the ODA has changed a lot between versions. The initial version of the virtualized ODA platform
supported only local VM repositories, and none of the virtual network setup was predefined. The evolution of
virtualization has now led to access to local or shared repositories, as well as the possibility to set up VLANs, which are
needed to segment databases and apps. ODA patch 2.8 allows shared repositories and a simplified way to set up VLANs.
Preparing for virtualization on the ODA requires making decisions that need to be made at the time of
deployment of the appliance. Due to the volatile nature of the appliance software, sometimes it can be hard to make
design choices without having to reverse course. There are a few decisions that need to be made prior to deployment:
•
Bare metal or virtualized?
•
Shared or local repository?
•
How many CPUs for the Database VM or ODA_Base?
The key decision is to decide between bare metal or virtualization. Once either is selected, it is very hard to
revert this decision back because doing so requires a complete reinstallation of the system. The local repository
option allows 250GB in an ODA v1 and 350GB in an ODA X3-2 to be made available for template management. This
is superseded by the shared repository option at the cost of losing space from the DATA and RECO diskgroups. The
shared repository option allows for higher availability of the virtual machines. With local repositories, a VM will only
start on the node it was registered; whereas in the shared repository mode, a VM can failover to a different node if one
is unavailable.
The other important sizing consideration is ensuring that the Database VM is sized correctly. The ODA's primary
focus is the database, such that a virtualized ODA contains a special, optimized VM called ODA_BASE that has
exclusive access to the shared disk, which is needed to ensure optimal database performance. ODA_BASE is a prebuilt
OVM template that has all the specific components that are needed for the Oracle Clusterware and the database.
The design is a very important aspect of virtualizing the ODA. Figure
10-1
shows a basic architecture of the
appliance virtualized. Since the ODA is a set on two physical servers, there are two main components that need to be
deployed on the ODA as part of a virtualization exercise:
•
Dom0 or the Virtualization controller
•
ODA_BASE or the customer VM specific for the ODA
