This is a very interesting idea! A couple of clarifications: 1. With the "2 satellite configuration", the data will always remain fully reconciled; in other words, there is no need to keep the data siloed. Is that correct? 2. Can a Cassandra cluster have two tables coexist, one with a primary/secondary concept and another active-active?
Jaydeep On Thu, 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 >
