Running Cassandra Workloads as a Managed Service with Amazon Keyspaces - CQL Compatible and Serverless
Manage wide-column data with an Apache Cassandra-compatible CQL API and eliminate operational overhead with serverless on-demand capacity. This article covers choosing between provisioned mode and on-demand mode, plus multi-Region replication.
Overview of Keyspaces
Amazon Keyspaces (for Apache Cassandra) is a fully managed wide-column database service compatible with Apache Cassandra. You can use CQL (Cassandra Query Language) as-is and connect with existing Cassandra drivers and tools. With its serverless architecture, no capacity management is needed after table creation. When running a self-managed Cassandra cluster, operational tasks such as node addition/removal, compaction, repair, and backup are required, but Keyspaces automates all of these. Like DynamoDB, it follows a serverless model, but Keyspaces differs by offering flexible querying through CQL and compatibility with the Cassandra ecosystem.
Capacity Modes and Data Model
Keyspaces offers two capacity modes: on-demand and provisioned. On-demand mode is fully pay-per-request, suitable for workloads with unpredictable traffic patterns. Provisioned mode lets you pre-configure read/write capacity units, optimizing costs for predictable workloads. Combined with Auto Scaling, provisioned mode can also automatically adjust to load changes. The data model requires the same partition key and clustering key design as Cassandra, where partition key selection determines performance and scalability. It supports major Cassandra data types including static columns, TTL (Time to Live), and counter columns.
Multi-Region and Operations
Multi-Region replication places table replicas across multiple Regions, reducing cross-Region latency. An active-active configuration enables both reads and writes in each Region, with automatic failover handling during Region outages. Point-in-time recovery (PITR) lets you restore a table to any point within the past 35 days, enabling recovery from accidental operations or data corruption. Encryption is enabled by default for both at-rest (AWS owned keys, customer managed keys) and in-transit (TLS). CloudWatch metrics monitor request counts, latency, and throttling events for capacity adjustment. For Cassandra data modeling, related books on Amazon can also be a helpful reference.
Keyspaces Pricing
Keyspaces pricing consists of capacity mode and storage charges. On-demand mode costs approximately $0.00000178 per write request unit (WRU) and approximately $0.000000356 per read request unit (RRU). Provisioned mode costs approximately $0.000742 per write capacity unit (WCU) per hour and approximately $0.0001484 per read capacity unit (RCU) per hour. Storage costs approximately $0.25 per GB per month. Multi-Region replication incurs additional charges for storage in each Region and replication writes.
Summary
Amazon Keyspaces is a Cassandra-compatible fully managed wide-column database that combines flexible CQL querying with zero operational overhead through its serverless architecture. Multi-Region replication with active-active configuration and PITR recovery capabilities deliver high availability and data protection.