You shouldn’t decom an entire DC before removing it from replication. —
Jon Haddad Rustyrazorblade Consulting rustyrazorblade.com On Mon, Apr 8, 2024 at 6:26 AM Michalis Kotsiouros (EXT) via user < user@cassandra.apache.org> wrote: > Hello community, > > In our deployments, we usually rebuild the Cassandra datacenters for > maintenance or recovery operations. > > The procedure used since the days of Cassandra 3.x was the one documented > in datastax documentation. Decommissioning a datacenter | Apache > Cassandra 3.x (datastax.com) > <https://docs.datastax.com/en/cassandra-oss/3.x/cassandra/operations/opsDecomissionDC.html> > > After upgrading to Cassandra 4.1.4, we have realized that there are some > stricter rules that do not allo to remove the replication when active > Cassandra nodes still exist in a datacenter. > > This check makes the above-mentioned procedure obsolete. > > I am thinking to use the following as an alternative: > > 1. Make sure no clients are still writing to any nodes in the > datacenter. > 2. Run a full repair with nodetool repair. > 3. Run nodetool decommission using the --force option on every node in > the datacenter being removed. > 4. Change all keyspaces so they no longer reference the datacenter > being removed. > > > > What is the procedure followed by other users? Do you see any risk > following the proposed procedure? > > > > BR > > MK >
