Our developers are having issues when using a 2.1.1 cluster than they are not seeing on a different 2.0.1 cluster, so we would like to downgrade the 2.1.1 cluster.
I thought it would have been possible to remove a server from the cluster, yum downgrade it and re-add, however I am unable to rebalance the node back in - it baoils saying node isn't ready.
Is there a support method of downgrading?
Could you give us more information about the problem you have with 2.1.1 or even when you try to rebalance?
As you said you can add nodes to you cluster and you should be able to remove them without issue.
Since you do not provide lot of information, logs, configuration, version, OS, size of the database, number of buckets... it is hard to help.
You can look at this page for the useful information to debug a cluster problem:
OK, let me re-phrase the question...
If you have a 3-node cluster, all running Couchbase 2.1.1, can you add a 4th node running Couchbase 2.0.0 and have the cluster balance across all four nodes? I.e. can you mixes 2.1 and 2.0 nodes in this matter.
As far as I remember you can't mix couchbase servers with different versions in one couchbase cluster. You can't even have 1 CB 2.1.1 on Windows and 1 CB 2.1.1 on Linux in one cluster.
Oh, found that in docs: http://docs.couchbase.com/couchbase-manual-2.2/#supported-platforms