Oracle B32100-01 Benutzerhandbuch

Overview of High Availability Configurations

Oracle Application Server Installation Guide

passive node mounts the shared storage and runs the Oracle Application Server 
instance.

The most common properties of an OracleAS Cold Failover Cluster configuration 
include:

■

Shared storage

The Oracle home for the Oracle Application Server instance is typically installed 
on storage that is shared by the nodes in the OracleAS Cold Failover Cluster 
topology. The passive Oracle Application Server instance has access to the same 
Oracle binaries, configuration files, and data as the active instance.

■

Virtual hostname

During OracleAS Infrastructure installation, you can specify a virtual hostname in 
the Specify Virtual Hostname screen. This OracleAS Infrastructure virtual 
hostname can be managed by a hardware cluster or a load balancer and is used by 
the middle-tier and OracleAS Infrastructure components to access the OracleAS 
Infrastructure. This is regardless of whether the OracleAS Infrastructure is in a 
single node installation, in the OracleAS Cold Failover Cluster solution, or in the 
OracleAS Clusters solution.

The virtual hostname is associated with a virtual IP. This is the name that gives the 
Oracle Application Server middle tiers a single system view of the OracleAS 
Infrastructure with the help of a hardware cluster or load balancer. This name-IP 
entry must be added to the DNS that the site uses, so that the middle-tier nodes 
can associate with the OracleAS Infrastructure without having to add this entry 
into their local /etc/hosts (or equivalent) file. For example, if the two physical 
hostnames of the hardware cluster are node1.mycompany.com and 
node2.mycompany.com

, the single view of this cluster can be provided by the 

name selfservice.mycompany.com. In the DNS, selfservice maps to the 
virtual IP address of the OracleAS Infrastructure, which either floats between 
node1

 and node2 via a hardware cluster or maps to node1 and node2 by a load 

balancer, all without the middle tier knowing which physical node is active and 
actually servicing a particular request.

You cannot specify a virtual hostname during Oracle Application Server 
middle-tier installation, but you can still use a virtual hostname via a hardware 
cluster or load balancer by following the post-installation configuration steps for 
cold failover cluster middle tiers. 

■

Failover procedure

An active-passive configuration also includes a set of scripts and procedures to 
detect failure of the active instance and to failover to the passive instance while 
minimizing downtime.

The advantages of an OracleAS Cold Failover Cluster configuration include:

■

Increased availability

If the active instance fails for any reason or must be taken offline, an identically 
configured passive instance is prepared to take over at any time.

■

Reduced operating costs

In an active-passive configuration only one set of processes is up and serving 
requests. Management of the active instance is generally less than managing an 
array of active instances.