Cassandra backups in multi region setup

Google Cloud Apigee
1

Hello Apigee users,

I have a question about backup configuration in a multi-region setup. We’re currently running two data centers (dc-1 and dc-2), each with three Cassandra replicas. Right now, we have backups enabled in both regions, but I’d like to better understand if this is necessary.

My specific questions:

Single node failure: If one Cassandra pod goes down in dc-2 (due to a node fault, for example), we would remove that node and add a new one. The new node would then replicate data from the remaining nodes in the cluster. This part seems clear.

Complete regional failure: What happens if all Cassandra nodes in dc-2 go down? In this scenario:

Is restoring from backups the only recovery option?
Or can new Cassandra nodes in dc-2 replicate the necessary data directly from dc-1?

Overall goal: I’m trying to understand how backup and recovery work in a multi-region scenario. In a single-region setup, it’s straightforward—all organization data is in one region, so backup restoration is the clear recovery path. But with multi-region replication, I’m not sure whether backups in both regions are required or if cross-region replication can handle disaster recovery.

Any insights would be appreciated!

1 Like
2

The hybrid cassandra backup/restore is intended for a full disaster/data loss scenario.

In your case, your dc-2 is gone.. then you reinstall a new dc2 and follow the instructions for that process, not a backup restore.

3

meaning, enabling backup for one dc (for ex dc-1) is good for just in case scenarios, it doesn’t add any value by enabling backups in all the DCs correct?

Thanks for your response

4

Let’s say you have DC-1, and DC-2.

You enable backups for DC-1 and it’s stored in the same geolocation as DC-1. If something happens to that geolocation, it could be now you have no DC-1 AND no backups..

5

Understood, Let’s say I bring up new nodes in DC-1 and replicate from DC-2 ? is it possible?

6

Instead of calling it DC-1 and DC-2, you can consider is DC-Y and DC-Z as in each region is equal, neither are more important than the other, and you can replicate any direction