Hi, I know it is "Not Supported and also Not Advised", but currently we have half of our cassandra cluster on 1.2.9 and the other half on 2.0.0 as we got stuck during upgrade. We know already that it was not very wise decision but that's what we've got now.
I have basically two questions. First, it would really help us if there was a way how to make request to newer cassandra work with data on older cassandra. We get Caused by: com.datastax.driver.core.exceptions.UnavailableException: Not enough replica available for query at consistency ONE (1 required but only 0 alive), which is surely caused by the fact that the newer nodes see the older as DOWN in nodetool ring. We "solve" this problem by connecting to the older nodes which see the whole cluster as online but it would help us deploying newer version of our application if could connect to 2.0.0 as well. Second, to avoid any future problems when upgrading, is there any documentation on what is incompatible between 1.2.x line and 2.0.x, what is not supposed to work together and what are the recommended steps? I don't see any warning regarding incompatibility of the gossip (?) protocol between 2.0.0 and 1.2.9 causing the described problem in the official documentation "Changes impacting upgrade". Thank you Jiri Horky
