High availability through clustering

A cluster is a group of connected machines that work together as a single system. When one machine in a cluster fails, cluster managing software transfers the workload of the failed machine onto other machines.

Heartbeat monitoring

To detect a failure on one machine in the cluster, failover software can use heartbeat monitoring or keepalive packets between machines to confirm availability. Heartbeat monitoring involves system services that maintain constant communication between all the machines in a cluster. If a heartbeat is not detected, failover to a backup machine starts.

IP address takeover

When there is a failure on one machine in the cluster, cluster managers can transfer workload from one machine to another by transferring the IP address from one machine to another. This is called IP address takeover, or IP takeover. This transfer is invisible to client applications, which continue to use the original IP address, unaware that the physical machine to which that IP address maps has changed.

The DB2® High Availability Feature enables integration between IBM® DB2 server and cluster managing software.