Database Reference
In-Depth Information
Oracle 11.2.0.2 introduced a new option for bonding multiple interconnect networks with an Oracle Redundant
Interconnect feature called Cluster High Availability IP (HAIP), which provides HA and bonds the interfaces for
aggregation at no extra cost to the Oracle environment. Oracle HAIP can take up to four NICs for the private network.
Chapter 9 details some best practices for private network configuration. To increase the scalability of the Oracle
RAC database, some advanced network solutions have been introduced. For example, as alternatives, 10g GbE
network and InfiniBand network are widely used for the private interconnect, to alleviate the potential performance
bottleneck.
In Oracle Clusterware 12cR1, Flex Clusters are introduced as a new option. If you use this option, Leaf Nodes are
not required to have direct access to the shared storage, while Hub Nodes are required to have direct access to the
shared storage, like the cluster nodes in an 11gR2 cluster. Figure
1-2
also illustrates the Flex Cluster structure where
servers 1 to 3 are Hub Nodes that have direct access to storage, while server 4 is a Leaf Node that does not connect to
shared storage and relies on a Hub Node to perform I/O operations. In release 12.1, all Leaf Nodes are in the same
public and private network as the Hub Nodes.
It is recommended to verify that the hardware and software configuration and settings comply with Oracle RAC
and Clusterware requirements, with one of these three verification and audit tools depending on the system:
•
For a regular RAC system, use RACCheck RAC Configuration Audit Tool (My Oracle Support
[MOS] note ID 1268927.1)
•
For an Oracle Exadata system, run Exachk Oracle Exadata Database Machine exachk or
HealthCheck (MOS note ID 1070954.1)
•
For an Oracle Database Appliance, use ODAchk Oracle Database Appliance (ODA)
configuration Audit Tool (MOS note ID: 1485630).
RAC Components
In order to establish an Oracle RAC infrastructure, you need to install the following two Oracle licensed products:
•
Oracle Grid Infrastructure: This combines Oracle Clusterware and Oracle ASM. Oracle
Clusterware clusters multiple interconnected servers (nodes). Oracle ASM provides the
volume manager and database file system that is shared by all cluster nodes.
•
Oracle RAC: This coordinates and synchronizes multiple database instances to access the
same set of database files and process transactions on the same database.
Figure
1-3
shows the architecture and main components of a two-node Oracle RAC database. The RAC nodes
are connected by the private interconnect network that carries the Clusterware heartbeat as well as the data transfer
among the RAC nodes. All the RAC nodes are connected to shared storage to allow them to access it. Each RAC node
runs Grid Infrastructure, which includes Oracle Clusterware and Oracle ASM. Oracle Clusterware performs cluster
management, and Oracle ASM handles shared storage management. Oracle RAC runs above the Grid Infrastructure
on each RAC node to enable the coordination of communication and storage I/O among the RAC database instances.
In the next two sections, we will discuss the functionality and components of these two Oracle products.
