I was working with a customer who wanted to have a database replicating data bi-directional towards another database by means of InfoSphere Data Replication (IIDR aka CDC), but also wanted to have a fail-over mechanism in place in conjunction with the bought replication solution.
An "out of the box" setup for a Db2 cluster would be defined as follows: a Primary Db2 database server put in an HADR setup. If you want to have fail-overs automated, add TSA on top of it to act as a guardian.