The migration process that you need to follow depends on the type of server and the type of data you need to migrate. Migrating to a cluster is not supported. Therefore you must migrate to a standalone node where the new version of WebSphere Portal is installed, and then set up the cluster.
Migrate the primary node (as opposed to a secondary node) from the earlier portal
environment. Migrating a secondary node can lead to security problems.
The WebSphere Application Server V6.1 node name must be the same as the earlier server's managed node. If you have already installed WebSphere Portal and did not specify the same node name during installation as the earlier server's cluster managed node name, you can change the node name.
If you want to migrate clustered environment to WPS 6.1 then Install and configure a new primary WebSphere Portal v6.1 server as a stand-alone server, run the WebSphere Portal v6.1 migration tool tasks to migrate the old clustered portal environment to the standalone server, install the deployment manager server and migrate its configuration from the earlier deployment manager server, federate the primary portal server into the new Network Deployment cell, create the new portal cluster, install the secondary portal server and add it to the cluster.