The total number of replicas across the cluster. A cluster (by default) consists of 256 tokens, which are uniformly distributed across all servers in the Cassandra datacenter. Each vnode receives one token in the ring. The token value determines the node’s position in the ring and its range of data. Each node gets assigned with a token, which is essentially a random number from the range. Each node being responsible for one or more ranges of the data. The ring is then divided into ranges equal to the number of nodes. Cassandra tries to place the replicas on different racks.Ī physical virtual machine running Cassandra software.Ĭonceptually, the data managed by a cluster is represented as a ring. This typically consists of multiple physical locations, keyspaces, and physical servers.Ī logical deployment construct in AWS that maps to an AWS CloudFormation StackSet, which consists of one or many CloudFormation stacks to deploy Cassandra.Ī group of nodes configured as a single replication group.Ī datacenter is deployed with a single CloudFormation stack consisting of Amazon EC2 instances, networking, storage, and security resources.Ī datacenter consists of at least one rack. If you’re already familiar with Cassandra or AWS deployments, this can serve as a refresher. Here’s a short introduction to standard Cassandra resources and how they are implemented with AWS infrastructure. is one customer who migrated to DynamoDB and observed significant savings. For more information, see Moving to Amazon DynamoDB from Hosted Cassandra: A Leap Towards 60% Cost Saving per Year.ĪWS provides options, so you’re covered whether you want to run your own NoSQL Cassandra database, or move to a fully managed, serverless DynamoDB database. Several customers who have been using large Cassandra clusters for many years have moved to DynamoDB to eliminate the complications of administering Cassandra clusters and maintaining high availability and durability themselves. Integration with AWS Identity and Access Management (IAM) enables DynamoDB customers to implement fine-grained access control for their data security needs. DynamoDB is fully managed, serverless, and provides multi-master cross-region replication, encryption at rest, and managed backup and restore. In this post, we outline three Cassandra deployment options, as well as provide guidance about determining the best practices for your use case in the following areas:īefore we jump into best practices for running Cassandra on AWS, we should mention that we have many customers who decided to use DynamoDB instead of managing their own Cassandra cluster.

Given the number of possible deployment topologies, it’s not always trivial to select the most appropriate strategy suitable for your use case. When combined, you can deploy Cassandra, allowing you to scale capacity according to your requirements. AWS customers that currently maintain Cassandra on-premises may want to take advantage of the scalability, reliability, security, and economic benefits of running Cassandra on Amazon EC2.Īmazon EC2 and Amazon Elastic Block Store (Amazon EBS) provide secure, resizable compute capacity and storage in the AWS Cloud. Note: AWS also now offers Amazon Keyspaces (for Apache Cassandra), a scalable, serverless, highly available, and fully managed Apache Cassandra–compatible database service.Īpache Cassandra is a commonly used, high performance NoSQL database.

Ec2 instance ephemeral storage