Moving back to 1.2.10. What is the procedure roll back from 2.0.1?
Changes in the system schema seem to make this quite difficult.
First, unfortunately downgrade is not, in my understanding, a supported operation.
In my efforts Iíve now completely taken DC3 offline and already tried:
Are you seeing the new schema on the 1.2.10 nodes?
If the schema has been modified globally via gossip, I don't understand how your 1.2.10 nodes are currently working. It seems like there may be a risk of them not working if you restart them?
If the schema changes have been seen globally, the safest solution is to dump, drop, and re-create your schema. This is likely to require a downtime across all DCs. You could probably do this semi-online by doing the (theoretical) clone-a-keyspace-with-hard-links operation, but that would require application changes/synchronization etc...