Amazon ElastiCache for Redis Documentation

Amazon ElastiCache for Redis is a managed Redis-compatible in-memory data structure service that can be used as a data store or cache. It is designed to provide the ease-of-use and power of Redis along with the availability, reliability, scalability, security, and performance suitable for demanding applications.

The service is designed to detect and recover from node failures or engine crashes. Utilizing Multi-AZ failover, you can spread replica nodes across multiple Amazon Web Services Availability Zones for high availability. If a primary node goes down, Amazon ElastiCache for Redis is designed to fail over to one of up to 5 read replicas.

Through the Amazon Web Services Management Console, you can launch a Cache Cluster or Replication Group and configure it to your requirements. We offer a range of node sizes, as well as push-button vertical scaling. Additionally, for Redis cluster mode enabled, you can resize your Redis clusters to scale-out and scale-in to adapt to changing demand.

Get started with Amazon ElastiCache for Redis by launching a new Cache Cluster or Replication Group using the Amazon Web Services Management Console or by making an API call. Resources are pre-configured with the appropriate parameters and settings, and Cache Parameter Groups so you can control and fine-tune your Redis environment. 

Amazon ElastiCache for Redis is designed to take care of time-consuming management tasks - such as software patch management, failure detection and recovery. You still get native access to the underlying Redis in-memory database environment, so you can use Amazon ElastiCache for Redis with your existing Redis tools and applications.

Amazon CloudWatch metrics can provide insights to your Redis resources. You can use the Amazon Web Services Management Console to view key operational metrics for your Redis instances, including compute, utilized memory, cache hit ratio, active connections, Redis replication and Redis commands.

Get notified via email or SMS of important events such as snapshot completion and scheduled node replacements. You can use the Amazon Web Services Management Console or APIs to subscribe to different events associated with your Redis resources.

You can tag your Cache Clusters and Redis snapshots for tracking and billing purposes. You can use the Cost Explorer to attribute costs to resources and Resource Groups to easily create and maintain collections of resources that share a common set of tags.

Increase availability by leveraging Multi-AZ with automatic failover functionality. You can take advantage of multiple Amazon Web Services Availability Zones to gain availability, and scale beyond the read capacity constraints of a single node. In case of primary node loss, the service is designed to automatically detect the failure and failover to a read replica to provide higher availability without the need for manual intervention. 

The service continuously monitors the health of your instances. In case a node experiences failure or a prolonged degradation in performance, the service is designed to restart the node and associated processes.

You can create snapshots of your clusters. Using these snapshots, or any Redis RDB-compatible snapshot stored on S3, you can then seed new ElastiCache for Redis clusters. You can also export your snapshots to an S3 bucket of your choice.

Global Datastore in Amazon ElastiCache for Redis is designed to provide managed, fast, reliable and secure cross-region replication. Global Datastore is designed to enable you to write to your ElastiCache for Redis cluster in one region and have the data available to be read from two other cross-region replica clusters, thereby enabling disaster recovery across regions. In the unlikely event of regional degradation, you can promote one of the healthy cross-region replica clusters to become the primary cluster with full read/write capabilities. (The cross-region capability is limited to the China Regions.) 

Using our APIs or with a few clicks in the Amazon Web Services Management Console, you can scale up or scale out your existing Redis configuration. For non-cluster mode, you can scale up to a larger node type, and go up to a maximum of 635.61 GiB. Scale up for Redis is designed to make a best effort to retain your existing data and requires Redis replication to succeed. 

ElastiCache for Redis cluster provides the ability to add and remove shards from a running cluster. You can scale-out or scale-in your Redis cluster workloads to adapt to changes in demand. ElastiCache is designed to resize the cluster by adding or removing shards and redistributing hash slots uniformly across the new shard configuration, all while the cluster continues to stay online and serve requests. Your existing node endpoints will persist.

You can use the Amazon ElastiCache API or the Amazon Web Services Management Console to upgrade your Redis clusters to the latest available engine version. The online engine upgrade process is designed to make a best effort attempt to retain your existing data and requires Redis replication to succeed.

You can add up to five Redis read replicas per primary node and serve high-volume application read traffic from multiple instances which can increase aggregate read throughput.

Global Datastore is designed so that you can write to your ElastiCache for Redis cluster in one region and have the data available to be read from two other cross-region replica clusters to enable low-latency local reads. (The cross-region capability is limited to the China Regions.)

Amazon ElastiCache for Redis is also designed to support failovers by detecting the primary node failure and promoting the replica to be the primary with minimal impact.

Amazon ElastiCache also provides cross region replication with Global Datastore. Global Datastore is designed to enable you to write to your ElastiCache for Redis cluster in one region and have the data available to be read from two other cross-region replica clusters. In the unlikely event of regional degradation, you can promote one of the cross-region replica clusters in the Global Datastore to become the primary cluster with full read/write capabilities. (The cross-region capability is limited to the China Regions.)

With Amazon ElastiCache for Redis, you can start small and scale your Redis data as your application grows. It is designed to allow you to scale your Redis Cluster environment up to 250 nodes and 250 shards. The online cluster resizing to scale-out and scale-in your Redis clusters helps you to scale your write capacity and adapt to changing demand. To scale read capacity, ElastiCache allows you to add up to five read replicas across multiple availability zones.

Amazon ElastiCache also enables cross region replication with Global Datastore. Global Datastore is designed to allow you to write to your ElastiCache for Redis cluster in one region and have the data available to be read from two other cross-region replica clusters. (The cross-region capability is limited to the China Regions.)

Amazon ElastiCache for Redis allows you to run your resources in Amazon Virtual Private Cloud (Amazon VPC). Amazon VPC enables you to isolate your Redis resources by specifying the IP ranges you wish to use for your nodes, and to connect to other applications inside the same Amazon VPC.

Amazon ElastiCache for Redis supports encryption in-transit and at-rest for internode communications. The encryption in-transit feature enables you to encrypt communications between clients and Redis server as well as between the Redis servers (primary and read replica nodes). The encryption at-rest feature allows you to encrypt your disk usage and backups in Amazon S3. Additionally, Amazon ElastiCache for Redis provides Amazon KMS integration that allows you to use your own customer managed CMK’s for encryption. Further, you can use the Redis AUTH command for an added level of authentication. 

Using the Amazon Identity and Access Management (IAM) features integrated with Amazon ElastiCache, you can control the actions that your Amazon IAM users and groups can take on Amazon ElastiCache resources. 

Amazon ElastiCache provides native support for JavaScript Object Notation (JSON) documents in addition to the data structures included in open source Redis. You can develop applications using the built-in commands designed and optimized for JSON documents. ElastiCache supports partial JSON document updates, as well as searching and filtering using the JSONPath query language. JSON support is available when using Redis 6.2 and above. 

Global Datastore in Amazon ElastiCache for Redis is designed to provide managed, fast, reliable and secure cross-region replication. Global Datastore is designed to enable you to write to your ElastiCache for Redis cluster in one region and have the data available to be read from two other cross-region replica clusters, thereby enabling low-latency reads and disaster recovery across regions.

Designed for real-time applications with a global footprint, Global Datastore for Redis supports low cross-region replication latency, increasing the responsiveness of your applications by providing geo-local reads closer to end users. In the unlikely event of regional degradation, you can promote one of the healthy cross-region replica clusters to become the primary cluster with full read/write capabilities. Once initiated, the promotion completes quickly, allowing your applications to remain available. Global Datastore uses encryption in-transit for cross-region data transfer traffic.

You can setup a Global Datastore by starting with an existing cluster, or by creating a new cluster to be used as a primary. You can create a Global Datastore in the Amazon Web Services Management Console for ElastiCache, or by downloading the latest Amazon SDK or CLI. Global Datastore is also supported on Amazon CloudFormation.

Global Datastore is designed to enable you to write to your ElastiCache for Redis cluster in one region and have the data available to be read from two other cross-region replica clusters to enable low-latency local reads. Global Datastore is designed for low cross-region replication latency so your applications can enjoy quick data access across regions. 

In the unlikely event of regional degradation, you can quickly promote one of the cross-region replica clusters in the Global Datastore to become the primary cluster with full read/write capabilities, allowing your applications to remain available. 

Leverage Redis' low latency for local read/writes in primary region and local reads in secondary regions. 

Global Datastore for Redis uses encryption in-transit for cross-region traffic. Additionally, you can encrypt your primary and secondary clusters using encryption at-rest. Each primary and secondary cluster can have a separate customer managed Amazon KMS key in Amazon Key Management Service (KMS) for encryption at rest. 

Global Datastore is designed to help you manage the complexity and operational burden of deploying, managing and replicating data in clusters across regions. You can set-up a Global Datastore by starting with an existing cluster, or by creating a new cluster to be used as primary. You can create a Global Datastore in the Amazon Amazon ElastiCache Management Console for ElastiCache, or by downloading the latest Amazon SDK or CLI. 

Global Datastore allows you to scale or upgrade regional clusters and is designed to ensure that all participating clusters are identically configured. You can add or remove regions from the Global Datastore, or promote a secondary region to become the primary. With any configuration change, Global Datastore is designed to ensure that cross-region replication is appropriately setup and all secondary clusters replicate data from the primary cluster.

Amazon ElastiCache for Redis is designed to provide managed, automatic scaling to maintain performance for your applications. It is designed to help you manage the complexity of managing cluster capacity for your workloads by allowing you to define resource requirements and scaling behaviors. ElastiCache will automatically scale your cluster based on these scaling plans, which can help you save on overall cloud spend by matching provisioned resources with changing capacity requirements.

Amazon ElastiCache for Redis uses Amazon Auto Scaling to manage scaling and Amazon CloudWatch metrics to determine when it is time to scale up or down. ElastiCache offers two types of scaling. First, you can use dynamic scaling, which scales your cluster automatically to keep a target metric, like free memory capacity, steady while load on your cluster changes. This enables you to increase performance of clusters when needed and reduce consumption when resources aren’t required. Second, you can use scheduled scaling to determine days and times to scale to accommodate predictable workload capacity changes. 

Amazon ElastiCache for Redis allows you to define auto scaling plans to define how your cluster scales. You can enable auto scaling on an existing or already running cluster. You can set up auto scaling in the Amazon Web Services Management Console, or through the Amazon SDK or CLI. ElastiCache uses Amazon Auto Scaling to manage the scaling of your cluster. 

When you set up auto scaling for Amazon ElastiCache for Redis, you apply a scaling policy based on predefined metrics, which enables you to optimize for your applications specific needs, whether that be performance or cost optimization. Amazon Auto Scaling sets targets based on your preferences and monitors your application to add or remove capacity as your demand changes. 

When your Amazon ElastiCache for Redis clusters exceed or fall below your target value, Amazon Auto Scaling adjusts your scaling capacity.  This is designed to allow you to continue to meet your performance requirements even when your workloads continuously change or become unpredictable. When your demand spikes, Amazon Auto Scaling increases your cluster capacity to help you maintain high performance.

Amazon ElastiCache for Redis auto scaling helps you optimize cost efficiency. When demand drops, Amazon Auto Scaling adjusts your clusters to help you avoid overprovisioning and overspending. Amazon ElastiCache for Redis auto scaling is free to use.

For additional information about service controls, security features and functionalities, including, as applicable, information about storing, retrieving, modifying, restricting, and deleting data, please see  https://docs.amazonaws.cn/en_us. This additional information does not form part of the Documentation for purposes of the Sinnet Customer Agreement for Amazon Web Services (Beijing Region), Western Cloud Data Customer Agreement for Amazon Web Services (Ningxia Region) or other agreement between you and Sinnet or NWCD governing your use of services of Amazon Web Services China Regions.