Migrating EJB Timers

If a GlassFish Server server instance stops or fails abnormally, it may be desirable to migrate the EJB timers defined for that stopped server instance to another running server instance.

Automatic timer migration is enabled by default for clustered server instances that are stopped normally. Automatic timer migration can also be enabled to handle clustered server instance crashes. In addition, timers can be migrated manually for stopped or crashed server instances.

• To Enable Automatic EJB Timer Migration for Failed Clustered Instances

• To Migrate EJB Timers Manually

To Enable Automatic EJB Timer Migration for Failed Clustered Instances

Automatic migration of EJB timers is enabled by default for clustered server instances that are stopped normally. If the Group Management Service (GMS) is enabled and a clustered instance is stopped normally, no further action is required for timer migration to occur. The procedure in this section is only necessary if you want to enable automatic timer migration for clustered server instances that have stopped abnormally.

Before You Begin

Automatic EJB timer migration can only be configured for clustered server instances. Automatic timer migration is not possible for standalone server instances.

• Enable delegated transaction recovery for the cluster.

  This enables automatic timer migration for failed server instances in the cluster.

  For instructions on enabling delegated transaction recovery, see Chapter 19, Administering Transactions, in Oracle GlassFish Server 3.1 Administration Guide.

To Migrate EJB Timers Manually

EJB timers can be migrated manually from a stopped source instance to a specified target instance in the same cluster if GMS notification is not enabled. If no target instance is specified, the DAS will attempt to find a suitable server instance. A migration notification will then be sent to the selected target server instance.

Note the following restrictions:

• If the source instance is part of a cluster, then the target instance must also be part of that same cluster.

• It is not possible to migrate timers from a standalone instance to a clustered instance, or from one cluster to another cluster.

• It is not possible to migrate timers from one standalone instance to another standalone instance.

• All EJB timers defined for a given instance are migrated with this procedure. It is not possible to migrate individual timers.

Before You Begin

The server instance from which the EJB timers are to be migrated should not be active during the migration process.

1. Verify that the source clustered server instance from which the EJB timers are to be migrated is not currently running.

   asadmin> list-instances source-instance

2. Stop the instance from which the timers are to be migrated, if that instance is still running.

   asadmin> stop-instance source-instance

   ---

   Note - The target instance to which the timers will be migrated should be running.

   ---

3. (Optional) List the currently defined EJB timers on the source instance, if desired.

   asadmin> list-timers source-cluster

4. Migrate the timers from the stopped source instance to the target instance.

   asadmin> migrate-timers --target target-instance source-instance

Example 5-20 Migrating an EJB Timer

The following example show how to migrate timers from a clustered source instance named football to a clustered target instance named soccer.

asadmin> migrate-timers --target soccer football

See Also

list-timers(1), migrate-timers(1), list-instances(1), stop-instance(1)