Configure transaction properties for peer recovery

Use this task to configure the transaction properties required for peer recovery of failed application servers in a cluster.

 

Overview

The transaction service requires a common configuration in order to be able to perform peer recovery between servers. This means that peer recovery processing can only take place between members of the same server cluster. Although a cluster can contain both v5 and v6 servers, high availability for peer recovery must only be enabled and configured if all servers in the cluster are at v6.

Configuring the transaction properties required for peer recovery is part of the overall task for configuring a cluster to use high availability support.

To configure the transaction properties required for peer recovery, complete the following steps:

 

Procedure

  1. Configure the transaction log directory setting for each server in the cluster. One can configure the location of the transaction log directory using either the WebSphere administrative console or commands.

    For peer recovery, each server in the cluster must be able to access the log directories of other servers in the same cluster. Interactions between the High Availability framework and the recovery log service prevent concurrent access to a single physical recovery log.

    When using WAS without High Availability support, one can leave the recovery log configuration for persistent services (such as the transactions service) unset. The application server assumes a default location within the appropriate profile directory. When High Availability support is enabled, this default may not be visible from all servers in the cluster (for example, if they are in different profiles or physical nodes.) As a result, it is recommended that the recovery log location be configured for each server in the cluster before enabling High Availability.

    The storage mechanism used to host recovery log files (for example, use IBM NAS and shared SCSI drives, but not simple network share) and access to that mechanism (for example, through a LAN), must support the file-based force operation that is used by the recovery log service to force data to disk.

    For more information about configuring transaction log directories, see Configuring transaction properties for an application server.

  2. Enable the High Availability function for the cluster, by completing the following steps on the cluster configuration panel of the WebSphere administrative console:

    1. In the administrative console, click Servers > Clusters > cluster_name.

    2. To enable high availability for a cluster, select the Enable high availability for persistent services option.

    3. To change the peer recovery characteristics for a specific server in the cluster, we need to create a new policy that has match criteria for the specific server.

      For more information about creating a new policy, see Creating a policy for a high availability group.

    For more information about enabling the High Availability function for a cluster, see Server cluster settings

  3. Change the WAS_TRANSACTION policy in the core group configuration

    1. In the administrative console, click Servers > Core Groups > DefaultCoreGroup > Policies > Cluster TM Policy.

    2. Change the policy properties to suit your recovery requirements. For example, one can enable or disable the use of hardware quorum support.

    For more information about configuring the WAS_TRANSACTION policy in the core group configuration, see Core groups.

 

See Also


Peer recovery of transactions