This describes the goal / intent but not the how. Isn’t a satellite approximately equivalent to a dc with only transient / witness replicas defined, and the nodetool command just a coordination of adding new transient replicas and removing the old? What’s the difference in implementation you’re proposing here ?
> On Nov 13, 2025, at 10:09 AM, Blake Eggleston <[email protected]> wrote: > > > Hello dev@, > > We'd like to propose CEP-58: Satellite Datacenters for adoption by the > community. CEP-58 proposes adding satellite data centers as an alternative to > the 3 full DC topology for achieving multi-DC high availability. Satellites > are small witness only datacenters (~1/15th full DC size) that replicate the > mutation journal, but otherwise don’t run the storage engine. This enables > transactionally consistent HA (via failover) with just 2 full DCs and one > satellite DC. > > This feature benefits users running clusters in a 1 or 2 DC topology for cost > or latency reasons, and is especially beneficial for paxos heavy workloads, > since only one of the paxos messages needs a satellite round trip. When used > in conjunction with witness replicas in the full DCs, single DC clusters > could become HA for less than the cost of adding a second datacenter. > > The CEP is linked here: > https://cwiki.apache.org/confluence/display/CASSANDRA/CEP-58:+Satellite+Datacenters, > but please keep the discussion on the dev list. > > Thanks! > > Blake Eggleston
