For mirroring purposes, and to provide a working copy of the Domain Administration Server (DAS), you must have:
One machine (machine1) that contains the original DAS.
A second machine (machine2) that contains a cluster with server instances running applications and catering to clients. The cluster is configured using the DAS on the first machine.
A third backup machine (machine3) where the DAS needs to be recreated in case the first machine crashes.
You must maintain a backup of the DAS from the first machine. Use asadmin backup-domain to backup the current domain.
The following steps are required to migrate the Domain Administration Server from the first machine (machine1) to the third machine (machine3).
Install the application server on the third machine just as it is installed on the first machine.
This is required so that the DAS can be properly restored on the third machine and there are no path conflicts.
Install the application server administration package using the command-line (interactive) mode. To activate the interactive command-line mode, invoke the installation program using the console option:
You must have root permission to install using the command-line interface.
Deselect the option to install default domain.
Restoration of backed up domains is only supported on two machines with same architecture and exactly the same installation paths (use same install-dir and domain-root-dir on both machines).
Copy the backup ZIP file from the first machine into the domain-root-dir on the third machine. You can also FTP the file.
Execute asadmin restore-domain command to restore the ZIP file onto the third machine:
asadmin restore-domain --filename domain-root-dir/sjsas_backup_v00001.zip domain1
You can backup any domain. However, while recreating the domain, the domain name should be same as the original.
Change domain-root-dir/domain1/generated/tmp directory permissions on the third machine to match the permissions of the same directory on first machine.
The default permissions of this directory are: ?drwx------? (or 700).
chmod 700 domain-root-dir/domain1/generated/tmp
The example above assumes you are backing up domain1. If you are backing up a domain by another name, you should replace domain1 above with the name of the domain being backed up.
Change the host values for the properties in the domain.xml file for the third machine:
Update the domain-root-dir/domain1/config/domain.xml on the third machine.
For example, search for machine1 and replace it with machine3. So, you can change:
<jmx-connector><property name=client-hostname value=machine1/>...
<jmx-connector><property name=client-hostname value=machine3/>...
Start the restored domain on machine3:
asadmin start-domain --user admin-user --password admin-password domain1
Change the DAS host values for properties under node agent on machine2.
Change agent.das.host property value in install-dir/nodeagents/nodeagent/agent/config/das.properties on machine2.
Restart the node agent on machine2.
Start the cluster instances using the asadmin start-instance command to allow them to synchronize with the restored domain.