Network Deployment (Distributed operating systems), v8.0 > Set up the application serving environment > Administer application servers > Manage application servers
Restarting an application server in recovery mode
When an application server instance with active transactions in progress restarts after a failure, the transaction service uses recovery logs to complete the recovery process. These logs, which each transactional resource maintains, are used to rerun any InDoubt transactions and return the overall system to a self-consistent state.
When you restart an application server in recovery mode:
- Transactional resources complete the actions in their recovery logs and then shut down. This action frees up any resource locks that the application server held prior to the failure.
- During the recovery period, only the subset of application server functions that are necessary for transactional recovery to proceed are available.
- The application server does not accept new work during the recovery process.
- The application server shuts down when the recovery is complete.
This recovery process begins as soon as all of the necessary subsystems within the application server are available. If the application server is not restarted in recovery mode, the application server can start accepting new work as soon as the server is ready, which might occur before the recovery work has completed.
Normally, this process is not a problem. However, situations exist when your operating procedures might not be compatible with supporting recovery work and new work simultaneously. For example, you might have a high availability environment where the work handled by the application server that failed is immediately moved to another application server. This backup application server then exclusively processes the work from the application server that failed until recovery has completed on the failed application server and the two application servers can be re-synchronized. In this situation, you might want the failing application server to only perform its transactional recovery process and then shut down. You might not want this application server to start accepting new work while the recovery process is taking place.
To prevent the assignment of new work to an application server that is going through its transaction recovery process, restart the application server in recovery mode.
When you restart a failed application server, the node agent for the node on which the failed application server resides must be running before you can restart that application server.
To be able restart an application server in recovery mode, perform the following steps before a failure occurs, and then restart the application server to enable the configuration changes:
Procedure
- If the server is monitored by a node agent, go to...
Servers | Server Types | WebSphere application servers | server_name | Server Infrastructure | Java and process management | Monitoring Policy
...and clear the option...
Automatic restart
- If a catastrophic failure occurs that leaves InDoubt transactions, run...
startServer.sh server_name -recovery
Results
The application server restarts in recovery mode, performs transactional recovery, and shuts down. Any resource locks that the application server held prior to the failure are released.
Transactional high availability
Start an application server
Related
startServer command
Start servers using scripting