3.11.5 Configuration using server exclusive for recovery (N-to-1 recovery system)
This subsection describes the configuration with one machine in the standby node for N machines in the executing nodes (server exclusive for recovery). This configuration is called an N-to-1 recovery system.
- Organization of this subsection
(1) Features of the system configuration
This is a system configuration for resolving the transaction and releasing the resources when there is a problem in certain J2EE server and a global transaction is used in a configuration with redundant J2EE servers. Use load balancer to create redundant J2EE servers for N machines.
The prerequisites of this configuration are as follows:
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Used in a system using global transaction
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The CORBA Naming Service is started as in-process
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The status file of transaction is saved to shared disk
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The operations are performed using Management Server
Application Server is subject to node switching in N-to-1 recovery system.
The resource adapters used in executing node are required for standby node as well when configuring N-to-1 recovery system. The following three types of configurations are described as an example for allocation of resource adapters and relation with system configuration:
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When the configuration of J2EE applications and resource adapters is the same for N executing node machines
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When the configurations of J2EE applications differ and all resource adapters are identical for N executing node machines
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When the configurations of J2EE applications and resource adapters differ for N executing node machines
The following are the examples of respective configurations:
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Note: For other legend items, see 3.2 Description of the system configuration.
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Note: For other legend items, see 3.2 Description of the system configuration.
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Note: For other legend items, see 3.2 Description of the system configuration.
- Features
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The executing node and standby node are in an N-to-1 ratio.
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A shared disk device is required. A volume group for the number of executing nodes (N) is required in the shared disk device.
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The CORBA Naming Service is started as in-process.
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The same resource adapters as in the executing node are required in the standby node. If a separate resource adapter is imported for each J2EE server in the executing node, you must import respective resource adapters for J2EE server in the standby node.
Also, a J2EE application is not required in the J2EE server on the standby node.
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When the database has a cluster configuration and if Application Server identifies only the virtual address (Logical address), you can still establish the connection.
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- Node switching flow
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When there is a failure in any of the J2EE servers started by Application Server in the executing node and when a J2EE server of the server exclusive for recovery is started by cluster software, the transaction used by the failed J2EE server is stopped. Thereafter, the cluster software of the J2EE server machine that failed and the cluster services of the corresponding standby nodes are stopped.
(2) Processes to be started on each machine
This subsection describes the required software and processes of the respective machines.
(a) Application Server machine (executing node)
You must install Application Server on the Application Server machine in the executing node.
The processes that must be started for using cluster software are as follows:
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Administration Agent
The required software and the processes to be invoked in the Application Server machine are different for each system configuration, depending on the used functions. Allocate the required software and the processes depending on the used functions.
(b) Application Server machine (Standby node)
You must install Application Server on the Application Server machine in the standby node.
Also, import all the resource adapters imported by J2EE server on Application Server machine of executing node.
The Application Server machine of standby node is in cold standby status.
However, the process does not start unless node switching takes place. When node switching is performed, the J2EE server process is started in recovery mode.
(c) Management Server machine
You must install Application Server on the Management Server machine.
Invoke the following process:
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Management Server
(d) Client machine
You must install the following software on Client machine:
- For a Web client configuration
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Web browser
- For an EJB client configuration
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uCosminexus Client (In Windows), Application Server