You won't notice any issues (all versions of cassandra are backwards compatible at least 1 version), and sstables will be slowly migrated to the new format as you compact, but you should still run it (upgradesstables) explicitly because when it comes time to run repair/boostrap/decommission/etc, you'll need all sstables on the same/current format.
On Thu, Oct 12, 2017 at 1:59 PM, Li, Guangxing <guangxing...@pearson.com> wrote: > Hi, > > I recently upgraded my test cluster from C* 2.0.9 to 2.1.19 and I did not > run 'nodetool upgradesstables' at all. Per my confirmation afterwards, > everything is fine. But according to documentation at > https://support.datastax.com/hc/en-us/articles/208040036- > Nodetool-upgradesstables-FAQ. > I need to do that. > So can someone tell me if I must do 'nodetool upgradesstables' after > upgrading each node from 2.0.9 to 2.1.19? > > Thanks. > > George. >