Oracle B32100-01 - Manual (Page 122)

Installation Order for High Availability Configurations
7-4 Oracle Application Server Installation Guide
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Increased scalability and performance
Multiple identically-configured instances provide the capability to have a
distributed workload shared among different machines and processes. New
instances can also be added as the demand of the application grows.
In general, the term OracleAS Clusters describes clustering at the Oracle Application
Server instance level. However, if it is necessary to call out the specific type of
instances being clustered, this document will use OracleAS Clusters (type) to
characterize the cluster solution. For example:
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two or more Oracle Identity Management instances are known as OracleAS
Cluster (Identity Management)
For details on OracleAS Cluster (Identity Management), see Chapter 9, "Installing in
High Availability Environments: OracleAS Cluster (Identity Management)" .
7.1.3 OracleAS Disaster Recovery
OracleAS Disaster Recovery configurations have the following characteristics:
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A production site and a standby site that mirrors the production site. Typically,
these sites are located some distance from each other to guard against site failures
such as floods, fires, or earthquakes. During normal operation, the production site
handles all the requests. If the production site goes down, the standby site takes
over and handles all the requests.
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Each site has all the hardware and software to run. It contains nodes for running
OracleAS Infrastructure and the middle tiers; load balancers; and DNS servers.
OracleAS Disaster Recovery includes OracleAS Infrastructure and middle tiers. For
details, see
Chapter 10, "Installing in High Availability Environments: OracleAS
Disaster Recovery" .
7.1.4 Summary of Differences
Table 7–1 summarizes the differences among the high availability configurations.
7.2 Installation Order for High Availability Configurations
For all high availability configurations, you install the components in the following
order:
Table 7–1 Differences Among the High Availability Configurations
OracleAS Cold
Failover Cluster
OracleAS Clusters
OracleAS Disaster
Recovery
Node configuration Active-Passive Active-Active Active-Passive
Hardware cluster Yes No Optional (hardware cluster
required only if you
installed the OracleAS
Infrastructure in an
OracleAS Cold Failover
Cluster configuration)
Virtual hostname Yes No Yes
Load balancer No Yes No 1
1 Geographic load balancer may be used to perform site name switchover.
Shared storage Yes No No