Amazon Keyspaces (for Apache Cassandra) Multi-Region Replication

With Amazon Keyspaces Multi-Region Replication, you can replicate your data with automated, fully-managed, active-active replication across the AWS Regions of your choice. You can improve both availability and resiliency from regional degradation while also benefiting from low latency local reads and writes for global applications. With Multi-Region Replication, Keyspaces asynchronously replicates data between Regions and data is typically propagated across in less than one second. Multi-Region Replication also eliminates the difficult work of resolving update conflicts and correcting for data divergence issues, enabling you to focus on your application. You can create a new multi-Region keyspace with just a few clicks on the AWS Management Console, or by using the AWS SDK or CLI. Learn more in the Keyspaces Developer Guide.

When you create a multi-Region keyspace, it consists of multiple replica keyspaces (one per AWS Region) that are treated as a single unit. Every Region has the same table schema. When an application writes data in one Region, Keyspaces uses storage-based asynchronous replication to propagate the writes across Regions with replication lag latencies typically less than one second, with no impact to your application's availability. In the unlikely event of a single-Region failure, you can simply point your application to one of the healthy Regions in your multi-Region keyspace. Because all Regions in a multi-Region keyspace support both reads and writes, there is no impact to your application's availability. Once the degraded Region comes back online, Keyspaces automatically syncs any missing data.

In Keyspaces, replication is active-active. You can now serve both reads and writes locally from the Regions closest to your customers with single-digit millisecond latency at any scale. With Multi-Region Replication, you can use Keyspaces for any global application that needs fast response time anywhere in the world.

With Multi-Region Replication, you can recover from a single AWS Region degradation by simply re-directing your application to a different Region in your multi-Region keyspace. Since Keyspaces offers active-active replication, there is no impact to your reads and writes. Keyspaces keeps track of any writes that have been performed on your multi-Region keyspace, but has not been yet propagated to all replica Regions. Once the Region comes back online, Keyspaces automatically syncs any missing changes allowing you to recover without any impact to your application's availability.

Multi-Region Replication uses fast, storage-based physical replication of data across Regions with replication lag typically less than one second. Replication in Keyspaces has little to no impact on your database queries since it does not share compute resources. This allows you to deal with high write throughput or bursty use cases without any impact to your application's availability.

Any changes made to data in any Region are replicated to other Regions in a multi-Region Keyspace. If applications update the same data in different Regions at about the same time, conflicts can arise. To help ensure eventual consistency, Keyspaces uses a cell-level timestamps and a last-writer-wins reconciliation between concurrent updates. Conflict resolution is fully managed and happens in the background without any impact to application's availability.