Database Reference
In-Depth Information
RAC Database. Optimal storage array design and configuration are the foundation of Oracle RAC Database design.
Understanding the optimal configuration of the storage array and how it contributes to the Oracle RAC Database
design help us make the right design decisions and establish the optimized infrastructure for Oracle RAC Database at
the very start of RAC Database configuration.
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oracle raC 12c introduced a new cluster architecture called oracle Flex Cluster in addition to the standard
cluster configuration, which is similar to the oracle 11gr2 cluster. in the oracle 12c Flex Cluster, there are two types of
cluster nodes: hub nodes and Leaf nodes. all the hub nodes have direct access to the shared storage, while the Leaf
nodes do not require direct access to shared storage. these Leaf nodes get data from the shared storage through hub
nodes. (please refer to Chapter 4 for more details.) this chapter will focus mainly on the standard cluster in which all the
nodes have direct access to the shared storage.
Note
Storage Architecture and I/O for RAC
Before we design the storage architecture, you need to understand the characteristics of I/O operations between
the Oracle RAC nodes and storage. The storage architecture for an Oracle RAC environment consists of OCR and
voting disk files of the Oracle Clusterware and database files and online redo logs for Oracle RAC Database. In theory,
these storage components can be stored in one physical volume. However, for optimal I/O performance and better
manageability, separate physical volumes may be created for each of the components.
To examine the I/O operations between the RAC Database nodes and the shared storage, for example, we create
four volumes for a two-node RAC Database as illustrated in Figure
5-1
. These four volumes are the two online redo
log volumes, one OCR and voting disk volume, and one data volume. Each of the two online redo log volumes is for
one one redo log thread of one RAC node. The data volume is for database files, control files, etc. Online redo logs and
database files are very critical components of the RAC Database.
RAC Node
RAC Node
RAC Database
Instance
RAC Database
Instance
Block Shipping
Oracle
Clusterware
Oracle
Clusterware
Server
Process
Server
Process
DBWn
LGWR
DBWn
LGWR
OCR/
Votingdisk
Online
Redo
Logs
Online
Redo
Logs
Data
Shared Storage
Figure 5-1.
Oracle RAC Database architecture
