> > Should upgradesstables not be run after every node is upgraded? If we need > to rollback then we will not be able to downgrade sstables to older version >
You can choose to (a) upgrade the SSTables one node at a time as you complete the binary upgrade, or (b) upgrade the binaries on all nodes then perform the SSTables upgrade in one hit. The choice is up to you but beware of the following caveats: - there's a performance hit when C* reads "n - 1" versions of SSTables so the sooner you do it the better - upgrading SSTables one node at a time is preferable due to the considerable performance hit or schedule it during low traffic periods The idea of a rollback isn't what you're accustomed to. There is no concept of "downgrade" in Cassandra. If you decide to rollback or backout of an upgrade implementation, it means that you have to restore your cluster from backups so be aware of that too. This is because once you've performed an upgrade, things like schema and system tables are generally no longer backward-compatible. Also, new incoming mutations are written in the new format which again is not backward-compatible. To cut to the chase -- the decision to upgrade the SSTables has zero bearing on rollback. Cheers!
