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12.15. Disaster Recovery

This section describes the steps required to restore HA broker cluster from backup.

The detailed instructions how to perform backup on replicated environment can be found here.

At this point we assume that backups are collected on regular basis from Master node.

Replication configuration of a cluster is stored internally in HA message store. This information includes IP addresses of the nodes. In case when HA message store needs to be restored on a different host with a different IP address the cluster replication configuration should be reseted in this case

Oracle provides a command line utility DbResetRepGroup to reset the members of a replication group and replace the group with a new group consisting of a single new member as described by the arguments supplied to the utility

Cluster can be restored with the following steps:

  • Copy log files into the store folder from backup

  • Use DbResetRepGroup to reset an existing environment. See an example below

    Example 12.9. Reseting of replication group with DbResetRepGroup

    java -cp je-5.0.58.jar com.sleepycat.je.rep.util.DbResetRepGroup -h ha-work/Node-5001/bdbstore -groupName TestClusterGroup -nodeName Node-5001 -nodeHostPort localhost:5001

    In the example above DbResetRepGroup utility from Berkeley JE of version 5.0.58 is used to reset the store at location ha-work/Node-5001/bdbstore and set a replication group to TestClusterGroup having a node Node-5001 which runs at localhost:5001.

  • Start a broker with HA store configured as specified on running of DbResetRepGroup utility.

  • Start replica nodes having the same replication group and a helper host port pointing to a new master. The store content will be copied into Replicas from Master on their start up.