Multi-DC Clustering & Distributed Data

[Jeroen Gordijn]

Hi,

I read the release notes of 2.5.6 and saw the Multi-DC Clustering which looks interesting. Going through the doc I see information about Cluster Singleton and Cluster Sharding and how it behaves with this new feature. I'm using Distributed Data and I am wondering if there are any changes for that?

More specific:

• Do all nodes in all DC's still participate in the same DD, or is it a DD set per DC?
• If they still gossip all data to all nodes in all DC's:
  
• Is there a change in the gossip interval that differs between within DC and over DC?
• Do all nodes gossip to other DC? Or is it like the described in the failure detection that only the oldest nodes do it?
  
• Currently the gossip prefers reachable over unreachable nodes, does this now take unreachable DC into account?
• Do you have any other info I missed with the questions above?

Thanks in advance!

Cheers,

Jeroen

[Johan Andrén]

Hi Jeroen,

I saw now that you already commented on the ticket, but for completeness sake:

All nodes still participate in the same DD (unless you limit with akka.cluster.distributed-data.role)

We have ideas for optimising the gossip so that less inter-DC gossip happens, between fewer cross-DC pairs but nothing is implemented yet. Tracked by issue: https://github.com/akka/akka/issues/23249

--

Johan

Akka Team