I see on the roadmap for 6.0 is multi-datacenter replication where a number of remote DCs can participate either synchronously or asynchronously in a cluster.
I am asking because I also saw a goal is to provide the ability for clients to read from their local DC storage, which is related to a use case I’m interested in.
Are there plans to allow certain data to be replicated globally and others to only be replicated within that region?
Presenting an entirely flat keyspace globally and providing that feature sounds… difficult and slow, so I think allowing each region to only present non-overlapping prefixes of their keyspaces globally would be fine. So like
us-east/ would be replicated to each other, but the rest of the keyspace would only be replicated within each region. The consistency would be like DR where the database version is consistent at some past point in time for reads. If you want to do a read-write transaction to a remote region’s keyspace you have to be prepared for very high latency, more conflicts, etc. I’m sure it would also add complications for transactions spanning the local and global prefix.
This would be a killer feature for complying with data protection and data sovereignty regulations while still sharing some data across countries where it is needed and lawful to transfer.