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

Seeding a New Cluster with an Externally Created Backup (Redis)

When you create a new Redis cluster, you can seed it with data from a Redis .rdb backup file. Seeding the cluster is useful if you currently manage a Redis instance outside of ElastiCache and want to populate your new ElastiCache for Redis cluster with your existing Redis data.

To see a new Redis cluster from a Redis backup created within Amazon ElastiCache, see Restoring From a Backup with Cluster Resizing.

When you use a Redis .rdb file to seed a new Redis cluster, you can do the following:

  • Upgrade from a nonpartitioned cluster to a Redis (cluster mode enabled) cluster running Redis version 3.2.4.

  • Specify a number of shards (called node groups in the API and CLI) in the new cluster that is different from the number of shards in the cluster that was used to create the backup file.

  • Specify a different node type for the new cluster—larger or smaller than that used in the cluster that made the backup. If you scale to a smaller node type, be sure that the new node type has sufficient memory for your data and Redis overhead. For more information, see Ensuring You Have Sufficient Memory to Create a Redis Snapshot.

  • Distribute your keys in the slots of the new Redis (cluster mode enabled) cluster differently than in the cluster that was used to create the backup file.

Note

You cannot seed a Redis (cluster mode disabled) cluster from an .rdb file created from a Redis (cluster mode enabled) cluster.

Important

  • You must ensure that your Redis backup data doesn't exceed the resources of the node. For example, you can't upload an .rdb file with 5 GB of Redis data to a cache.m3.medium node that has 2.9 GB of memory.

    If the backup is too large, the resulting cluster will have a status of restore-failed. If this happens, you must delete the cluster and start over.

    For a complete listing of node types and specifications, see Redis Node-Type Specific Parameters and Amazon ElastiCache Product Features and Details.

  • Encrypting a Redis .rdb file with Amazon S3 server-side encryption (SSE) is not supported.

Following, you can find topics that walk you through migrating your Redis cluster from outside ElastiCache for Redis to ElastiCache for Redis.

Step 1: Create a Redis Backup

To create the Redis backup from which you will seed your ElastiCache for Redis instance

  1. Connect to your existing Redis instance.

  2. Run either the Redis BGSAVE or SAVE operation to create a backup. Note where your .rdb file is located.

    BGSAVE is asynchronous and does not block other clients while processing. For more information, see BGSAVE at the Redis website.

    SAVE is synchronous and blocks other processes until finished. For more information, see SAVE at the Redis website.

For additional information on creating a backup, see Redis Persistence at the Redis website.

Step 2: Create an Amazon S3 Bucket and Folder

When you have created the backup file, you need to upload it to a folder within an Amazon S3 bucket. To do that, you must first have an Amazon S3 bucket and folder within that bucket. If you already have an Amazon S3 bucket and folder with the appropriate permissions, you can skip to Step 3: Upload Your Backup to Amazon S3.

To create an Amazon S3 bucket

  1. Sign in to the AWS Management Console and open the Amazon S3 console at https://console.aws.amazon.com/s3/.

  2. Follow the instructions for creating an Amazon S3 bucket in Creating a Bucket in the Amazon Simple Storage Service Console User Guide.

    The name of your Amazon S3 bucket must be DNS-compliant. Otherwise, ElastiCache cannot access your backup file. The rules for DNS compliance are:

    • Names must be at least 3 and no more than 63 characters long.

    • Names must be a series of one or more labels separated by a period (.) where each label:

      • Starts with a lowercase letter or a number.

      • Ends with a lowercase letter or a number.

      • Contains only lowercase letters, numbers, and dashes.

    • Names cannot be formatted as an IP address (e.g., 192.0.2.0).

    We strongly recommend that you create your Amazon S3 bucket in the same region as your new ElastiCache for Redis cluster. This approach will ensure the highest data transfer speed when ElastiCache reads your .rdb file from Amazon S3.

    Security Advisory

    To keep your data as secure as possible, make the permissions on your Amazon S3 bucket as restrictive as you can while still allowing the bucket and its contents to be used to seed your new Redis cluster.

To add a folder to an Amazon S3 bucket

  1. Sign in to the AWS Management Console and open the Amazon S3 console at https://console.aws.amazon.com/s3/.

  2. Choose the name of the bucket you will upload your .rdb file to.

  3. Choose Create folder.

  4. Type in a name for your new folder.

  5. Choose Save.

    Make note of both the bucket name and the folder name.

Step 3: Upload Your Backup to Amazon S3

It is now time to upload the .rdb file your created in Step 1: Create a Redis Backup to the Amazon S3 bucket and folder you created in Step 2: Create an Amazon S3 Bucket and Folder. For more information on this task, see Add an Object to a Bucket. Between steps 2 and 3, choose the name of the folder you created .

To upload your .rdb file to an Amazon S3 folder

  1. Sign in to the AWS Management Console and open the Amazon S3 console at https://console.aws.amazon.com/s3/.

  2. Choose the name of the Amazon S3 bucket you created in Step 2.

  3. Choose the name of the folder you created in Step 2.

  4. Choose Upload.

  5. Choose Add files.

  6. Browse to find the file or files you want to upload, then choose the file or files. To choose multiple files, hold down the Ctrl key while choosing a file name.

  7. Choose Open.

  8. Confirm the correct file or files are listed in the Upload dialog box, and then choose Upload.

It is important that you note the path to your .rdb file. For example, if my bucket name is myBucket and the path is myFolder/redis.rdb, you type myBucket/myFolder/redis.rdb. You need this path to seed the new cluster with the data in this backup.

For additional information, see Bucket Restrictions and Limitations in the Amazon Simple Storage Service Developer Guide.

Step 4: Grant ElastiCache Read Access to the .rdb File

To grant ElastiCache read access to the backup file

  1. Sign in to the AWS Management Console and open the Amazon S3 console at https://console.aws.amazon.com/s3/.

  2. Choose the name of the S3 bucket that contains your .rdb file.

  3. Choose the name of the folder that contains your .rdb file.

  4. Choose the name of your .rdb backup file. The name of the selected file will appear above the tabs at the top of the page.

    Image: File selected in S3 console

    File selected in S3 console

  5. Choose Permissions.

  6. If aws-scs-s3-readonly or one of the canonical IDs in the following list is not listed as a user, do the following:

    1. Choose + Add users.

    2. In the Enter an ID or email box, type the canonical ID for the region:

      • China (Beijing) Region: b14d6a125bdf69854ed8ef2e71d8a20b7c490f252229b806e514966e490b8d83

         

      • AWS GovCloud (US) Region: 40fa568277ad703bd160f66ae4f83fc9dfdfd06c2f1b5060ca22442ac3ef8be6

        Important

        The backup must be located in an S3 bucket in AWS GovCloud (US) for you to download it to a Redis cluster in AWS GovCloud (US).

      • All other regions – 540804c33a284a299d2547575ce1010f2312ef3da9b3a053c8bc45bf233e4353

    3. For Object access, choose Read and Write.

    4. For Permissions access, choose Read.

    5. Choose Save.

  7. Choose Overview.

  8. Choose Download.

Step 5: Seed the ElastiCache Cluster With the .rdb File Data

Now you are ready to create an ElastiCache cluster and seed it with the data from the .rdb file. To create the cluster, follow the directions at Creating a Cluster or Creating a Redis Cluster with Replicas from Scratch. Be sure to choose Redis as your cluster engine.

The method you use to tell ElastiCache where to find the Redis backup you uploaded to Amazon S3 depends on the method you use to create the cluster:

  • Seed the ElastiCache Cluster With the .rdb File Data Using the ElastiCache Console

    After you choose the Redis engine, expand the Advanced Redis settings section and locate Import data to cluster. In the Seed RDB file S3 location box, type in the Amazon S3 path for the files(s). If you have multiple .rdb files, type in the path for each file in a comma separated list. The Amazon S3 path will look something like myBucket/myFolder/myBackupFilename.rdb.

     

  • Seed the ElastiCache Cluster With the .rdb File Data Using the AWS CLI

    If you use the create-cache-cluster or the create-replication-group operation, use the parameter --snapshot-arns to specify a fully qualified ARN for each .rdb file. For example, arn:aws:s3:::myBucket/myFolder/myBackupFilename.rdb. The ARN must resolve to the backup files you stored in Amazon S3.

     

  • Seed the ElastiCache Cluster With the .rdb File Data Using the ElastiCache API

    If you use the CreateCacheCluster or the CreateReplicationGroup ElastiCache API operation, use the parameter SnapshotArns to specify a fully qualified ARN for each .rdb file. For example, arn:aws:s3:::myBucket/myFolder/myBackupFilename.rdb. The ARN must resolve to the backup files you stored in Amazon S3.

During the process of creating your cluster, the data in your Redis backup will be written to the cluster. You can monitor the progress by viewing the ElastiCache event messages. To do this, go to the ElastiCache console and choose Cache Events. You can also use the AWS ElastiCache command line interface or ElastiCache API to obtain event messages. For more information, see Viewing ElastiCache Events.