After decommissioning my cluster from 20 to 9 nodes using opscenter, I found all but one of the nodes had incorrect system.peers tables.
This became a problem (afaik) when using the python-driver, since this queries the peers table to set up its connection pool. Resulting in very slow startup times, because of timeouts.
The output of nodetool didn't seem to be affected. After removing the incorrect entries from the peers tables, the connection issues seem to have disappeared for us.
Would like some feedback on if this was the right way to handle the issue or if I'm still left with a broken cluster.
Attached is the output of nodetool status, which shows the correct 9 nodes. Below that the output of the system.peers tables on the individual nodes.