Clusters: Configuration: Migration

If a clustered server fails, Node Manager can automatically restart the server and its services on another machine. This page allows you to specify the machines where Node Manager can restart migratable servers and to specify the data source used during server migration.

Name	Description
Candidate Machines For Migratable Servers	The set of machines (and order of preference) on which Node Manager will restart failed servers. (Requires you to enable each server for automatic migration.) Each server can specify a subset of these cluster-wide candidates, which limits the machines on which the server can be restarted. Servers can also specify their own order of preference. MBean Attribute: `ClusterMBean.CandidateMachinesForMigratableServers` Changes take effect after you redeploy the module or restart the server.
Migration Basis	Controls the mechanism used for server and service migration. Database -- Requires the availability of a high-availability database, such as Oracle RAC, to store leasing information. Requires also configuring the `DataSourceForAutomaticMigration` attribute. Optionally also configure `AutoMigrationTableName` (default is "ACTIVE"), `AutoMigrationTableCreationPolicy`, and `AutoMigrationTableCreationDDLFile`. Consensus -- Stores the leasing information in-memory within a cluster member. This option requires Node Manager to be configured and running. Note: Within a WebLogic Server installation, you can only use one type of leasing. Although it is possible to implement multiple features that use leasing within your environment, each must use the same kind of leasing. MBean Attribute: `ClusterMBean.MigrationBasis` Changes take effect after you redeploy the module or restart the server.
Data Source For Automatic Migration	The data source used by servers in the cluster during migration. (You must configure each Migratable Server within the cluster to use this data source.) This setting applies only if the `MigrationBasis` attribute is set to `database`. MBean Attribute: `ClusterMBean.DataSourceForAutomaticMigration` Changes take effect after you redeploy the module or restart the server.
Auto Migration Table Name	Return the name of the table to be used for server migration. This setting applies only if the `MigrationBasis` attribute is set to `database`. If the `AutoMigrationTableCreationPolicy` is set to `Always`, then the table name format must be specified in the form `[[[mycatalog.]myschema.]mytablename`; for example `myschema.mytablename`. Each period symbol format is significant, where schema generally corresponds to username in many databases. When no table name is specified, the table name is simply `ACTIVE` and the database implicitly determines the schema according to the JDBC data source user. MBean Attribute: `ClusterMBean.AutoMigrationTableName` Changes take effect after you redeploy the module or restart the server.
Auto Migration Table Creation DDL File	The absolute file path of a custom DDL file for creating the automatic migration database table. This setting applies only if the `MigrationBasis` attribute is set to `database`, the `AutoMigrationTableCreationPolicy` attribute is set to `Always`, and the table name specified by the `AutoMigrationTableName` attribute does not already exist in the database. If the above conditions apply, and this setting is set to the default, then the system will try to find a default DDL file for the creating the leasing database table in `WL_HOME/server/db/DB_TYPE/leasing.ddl`. Note that the system ignores (skips) any `DROP` commands in the DDL file, and substitutes the value configured in the `AutoMigrationTableName` attribute for all occurrences of the word `ACTIVE` in the file. MBean Attribute: `ClusterMBean.AutoMigrationTableCreationDDLFile` Changes take effect after you redeploy the module or restart the server.
Auto Migration Table Creation Policy	Control automatic leasing table creation behavior. This setting applies only if the `MigrationBasis` attribute is set to `database`. `Disabled` Disables automatic leasing table creation. The behavior is same as manual table creation. Any singletons dependent on cluster leasing will fail to start unless the table defined by the `AutoMigrationTableName` already exists in the database. `Always` Force automatic leasing table creation if the table is not found. The default table name is "ACTIVE" and can be customized using the `AutoMigrationTableName` attribute. The SQL used to create the table when it is not found can be customized using the `AutoMigrationTableCreationDDLFile` attribute. MBean Attribute: `ClusterMBean.AutoMigrationTableCreationPolicy` Changes take effect after you redeploy the module or restart the server.
Member Death Detector Enabled	Enables faster Automatic Service Migration times with Database Leasing Basis. MBean Attribute: `ClusterMBean.MemberDeathDetectorEnabled` Changes take effect after you redeploy the module or restart the server.
Member Discovery Timeout	Gets the MemberDiscoveryTimeout value. This value defines the amount of time a server waits during or after startup to discover members that belong to the same cluster. This information is used to join or form a new cluster. MBean Attribute: `DatabaseLessLeasingBasisMBean.MemberDiscoveryTimeout` Minimum value: `10` Changes take effect after you redeploy the module or restart the server.
Leader Heartbeat Period	Gets the LeaderHeartbeatPeriod value. The cluster leader heartbeats a special leader heartbeat every period seconds to publish group view version and other cluster information. Members look at this heartbeat and perform any sync up operations if required. Minimum value: `1` Changes take effect after you redeploy the module or restart the server.
Additional Migration Attempts	A migratable server could fail to come up on every possible configured machine. This attribute controls how many further attempts, after the first one, should be tried. Note that each attempt specified here indicates another full circuit of migrations amongst all the configured machines. So for a 3-server cluster, and the default value of 3, a total of 9 migrations will be attempted. If it is set to -1, migrations will go on forever until the server starts. MBean Attribute: `ClusterMBean.AdditionalAutoMigrationAttempts` Changes take effect after you redeploy the module or restart the server.
Pause Time Between Migration Attempts	Controls how long of a pause there should be between the migration attempts described in getAdditionalAutoMigrationAttempts(). Note that this delay only happens when the server has failed to come up on every machine. MBean Attribute: `ClusterMBean.MillisToSleepBetweenAutoMigrationAttempts` Changes take effect after you redeploy the module or restart the server.

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Clusters: Configuration: Migration

Configuration Options