Menu
Amazon ElastiCache
User Guide (API Version 2015-02-02)

Scaling Up Single-Node Redis (cluster mode disabled) Clusters

When you scale up a single-node Redis cluster, ElastiCache performs the following process, whether you use the ElastiCache console, the AWS CLI, or the ElastiCache API.

  1. All reads from and writes to the cache cluster are blocked.

  2. A new cache cluster with the new node type is spun up in the same Availability Zone as the existing cache cluster.

  3. The cache data in the existing cache cluster is copied to the new cache cluster. How long this process takes depends upon your node type and how much data is in the cache cluster.

  4. Reads and writes are resumed using the new cache cluster. Because the new cache cluster's endpoints are the same as they were for the old cache cluster, you do not need to update the endpoints in your application.

  5. ElastiCache deletes the old cache cluster.

Because writes to and reads from your cache cluster are blocked during the scale-up process, you should schedule the scale up for a time of low demand on your cache cluster.

As shown in the following table, your Redis scale-up operation is blocked if you have an engine upgrade scheduled for the next maintenance window. For more information on Maintenance Windows, see Maintenance Window.

Blocked Redis operations

Pending Operations Blocked Operations
Scale up Immediate engine upgrade
Engine upgrade Immediate scale up

Scale up and engine upgrade

Immediate scale up
Immediate engine upgrade

If you have a pending operation that is blocking you, you can do one of the following.

  • Schedule your Redis scale-up operation for the next maintenance window by clearing the Apply immediately check box (CLI use: --no-apply-immediately, API use: ApplyImmediately=false).

  • Wait until your next maintenance window (or after) to perform your Redis scale up operation.

  • Add the Redis engine upgrade to this cache cluster modification with the Apply Immediately check box chosen (CLI use: --apply-immediately, API use: ApplyImmediately=true). This unblocks your scale up operation by causing the engine upgrade to be performed immediately.

You can scale up a single-node Redis (cluster mode disabled) cluster using the ElastiCache console, the AWS CLI, or ElastiCache API.

Important

If your parameter group uses reserved-memory to set aside memory for Redis overhead, before you begin scaling be sure that you have a custom parameter group that reserves the correct amount of memory for your new node type. Alternatively, you can modify a custom parameter group so that it uses reserved-memory-percent and use that parameter group for your new cluster.

If you're using reserved-memory-percent, doing this is not necessary.

For more information, see Managing Reserved Memory (Redis).

Scaling Up Single-Node Redis (cluster mode disabled) Clusters (Console)

The following procedure describes how to scale up a single-node Redis cluster using the ElastiCache Management Console.

To scale up a single-node Redis cluster (console)

  1. Sign in to the AWS Management Console and open the ElastiCache console at https://console.aws.amazon.com/elasticache/.

  2. From the navigation pane, choose Redis.

  3. From the list of clusters, choose the cluster you want to scale up (it must be running the Redis engine, not the Clustered Redis engine).

  4. Choose Modify.

  5. In the Modify Cluster wizard:

    1. Choose the node type you want to scale to from the Node type list.

      The list identifies all the node types you can scale up to.

    2. If you're using reserved-memory to manage your memory, from the Parameter Group list, choose the custom parameter group that reserves the correct amount of memory for your new node type.

  6. If you want to perform the scale up process right away, choose the Apply immediately box. If the Apply immediately box is not chosen, the scale-up process is performed during this cluster's next maintenance window.

  7. Choose Modify.

    If you chose Apply immediately in the previous step, the cluster's status changes to modifying. When the status changes to available, the modification is complete and you can begin using the new cluster.

Scaling Up Single-Node Redis Cache Clusters (AWS CLI)

The following procedure describes how to scale up a single-node Redis cache cluster using the AWS CLI.

To scale up a single-node Redis cache cluster (AWS CLI)

  1. Determine the node types you can scale up to by running the AWS CLI list-allowed-node-type-modifications command with the following parameter.

    • --cache-cluster-id – Name of the single-node Redis cache cluster you want to scale up.

    For Linux, macOS, or Unix:

    Copy
    aws elasticache list-allowed-node-type-modifications \ --cache-cluster-id my-cache-cluster-id

    For Windows:

    Copy
    aws elasticache list-allowed-node-type-modifications ^ --cache-cluster-id my-cache-cluster-id

    Output from the above command looks something like this (JSON format).

    {
        "ScaleUpModifications": [
            "cache.m3.2xlarge", 
            "cache.m3.large", 
            "cache.m3.xlarge", 
            "cache.m4.10xlarge", 
            "cache.m4.2xlarge", 
            "cache.m4.4xlarge", 
            "cache.m4.large", 
            "cache.m4.xlarge", 
            "cache.r3.2xlarge", 
            "cache.r3.4xlarge", 
            "cache.r3.8xlarge", 
            "cache.r3.large", 
            "cache.r3.xlarge"
        ]
    }

    For more information, see list-allowed-node-type-modifications in the AWS CLI Reference.

  2. Modify your existing cache cluster specifying the cache cluster to scale up and the new, larger node type, using the AWS CLI modify-cache-cluster command and the following parameters.

    • --cache-cluster-id – The name of the cache cluster you are scaling up.

    • --cache-node-type – The new node type you want to scale the cache cluster up to. This value must be one of the node types returned by the list-allowed-node-type-modifications command in step 1.

    • --cache-parameter-group-name – [Optional] Use this parameter if you are using reserved-memory to manage your cluster's reserved memory. Specify a custom cache parameter group that reserves the correct amount of memory for your new node type. If you are using reserved-memory-percent you can omit this parameter.

    • --apply-immediately – Causes the scale-up process to be applied immediately. To postpone the scale-up process to the cluster's next maintenance window, use the --no-apply-immediately parameter.

    For Linux, macOS, or Unix:

    Copy
    aws elasticache modify-cache-cluster \ --cache-cluster-id my-redis-cache-cluster \ --cache-node-type cache.m2.xlarge \ --cache-parameter-group-name redis32-m2-xl \ --apply-immediately

    For Windows:

    Copy
    aws elasticache modify-cache-cluster ^ --cache-cluster-id my-redis-cache-cluster ^ --cache-node-type cache.m2.xlarge ^ --cache-parameter-group-name redis32-m2-xl ^ --apply-immediately

    Output from the above command looks something like this (JSON format).

    {
        "CacheCluster": {
            "Engine": "redis", 
            "CacheParameterGroup": {
                "CacheNodeIdsToReboot": [], 
                "CacheParameterGroupName": "default.redis3.2", 
                "ParameterApplyStatus": "in-sync"
            }, 
            "SnapshotRetentionLimit": 1, 
            "CacheClusterId": "my-redis-cache-cluster", 
            "CacheSecurityGroups": [], 
            "NumCacheNodes": 1, 
            "SnapshotWindow": "00:00-01:00", 
            "CacheClusterCreateTime": "2017-02-21T22:34:09.645Z", 
            "AutoMinorVersionUpgrade": true, 
            "CacheClusterStatus": "modifying", 
            "PreferredAvailabilityZone": "us-west-2a", 
            "ClientDownloadLandingPage": "https://console.aws.amazon.com/elasticache/home#client-download:", 
            "CacheSubnetGroupName": "default", 
            "EngineVersion": "3.2.4", 
            "PendingModifiedValues": {
                "CacheNodeType": "cache.m3.2xlarge"
            }, 
            "PreferredMaintenanceWindow": "tue:11:30-tue:12:30", 
            "CacheNodeType": "cache.m3.medium"
        }
    }

    For more information, see modify-cache-cluster in the AWS CLI Reference.

  3. If you used the --apply-immediately, check the status of the new cache cluster using the AWS CLI describe-cache-clusters command with the following parameter. When the status changes to available, you can begin using the new, larger cache cluster.

    • --cache-cache cluster-id – The name of your single-node Redis cache cluster. Use this parameter to describe a particular cache cluster rather than all cache clusters.

    Copy
    aws elasticache describe-cache-clusters --cache-cluster-id my-redis-cache-cluster

    For more information, see describe-cache-clusters in the AWS CLI Reference.

Scaling Up Single-Node Redis Cache Clusters (ElastiCache API)

The following procedure describes how to scale up a single-node Redis cache cluster using the ElastiCache API.

To scale up a single-node Redis cache cluster (ElastiCache API)

  1. Determine the node types you can scale up to by running the ElastiCache API ListAllowedNodeTypeModifications action with the following parameter.

    • CacheClusterId – The name of the single-node Redis cache cluster you want to scale up.

    Copy
    https://elasticache.us-west-2.amazonaws.com/ ?Action=ListAllowedNodeTypeModifications &CacheClusterId=MyRedisCacheCluster &Version=2015-02-02 &SignatureVersion=4 &SignatureMethod=HmacSHA256 &Timestamp=20150202T192317Z &X-Amz-Credential=<credential>

    For more information, see ListAllowedNodeTypeModifications in the Amazon ElastiCache API Reference.

  2. Modify your existing cache cluster specifying the cache cluster to scale up and the new, larger node type, using the ModifyCacheCluster ElastiCache API action and the following parameters.

    • CacheClusterId – The name of the cache cluster you are scaling up.

    • CacheNodeType – The new, larger node type you want to scale the cache cluster up to. This value must be one of the node types returned by the ListAllowedNodeTypeModifications action in step 1.

    • CacheParameterGroupName – [Optional] Use this parameter if you are using reserved-memory to manage your cluster's reserved memory. Specify a custom cache parameter group that reserves the correct amount of memory for your new node type. If you are using reserved-memory-percent you can omit this parameter.

    • ApplyImmediately – Set to true to cause the scale-up process to be performed immediately. To postpone the scale-up process to the cluster's next maintenance window, use ApplyImmediately=false.

    Copy
    https://elasticache.us-west-2.amazonaws.com/ ?Action=ModifyCacheCluster &ApplyImmediately=true &CacheClusterId=MyRedisCacheCluster &CacheNodeType=cache.m2.xlarge &CacheParameterGroupName redis32-m2-xl &Version=2015-02-02 &SignatureVersion=4 &SignatureMethod=HmacSHA256 &Timestamp=20150202T192317Z &X-Amz-Credential=<credential>

    For more information, see ModifyCacheCluster in the Amazon ElastiCache API Reference.

  3. If you used ApplyImmediately=true, check the status of the new cache cluster using the ElastiCache API DescribeCacheClusters action with the following parameter. When the status changes to available, you can begin using the new, larger cache cluster.

    • CacheClusterId – The name of your single-node Redis cache cluster. Use this parameter to describe a particular cache cluster rather than all cache clusters.

    Copy
    https://elasticache.us-west-2.amazonaws.com/ ?Action=DescribeCacheClusters &CacheClusterId=MyRedisCacheCluster &Version=2015-02-02 &SignatureVersion=4 &SignatureMethod=HmacSHA256 &Timestamp=20150202T192317Z &X-Amz-Credential=<credential>

    For more information, see DescribeCacheClusters in the Amazon ElastiCache API Reference.