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Amazon ElastiCache User Guide Table of Contents What Is Amazon ElastiCache? ......................................................................................................... 1 Amazon ElastiCache Videos .................................................................................................... 2 Introductory Videos ........................................................................................................ 2 Advanced Videos .......................................................................................................... 2 Are You a First-Time ElastiCache User? .................................................................................... 3 Data Model .......................................................................................................................... 4 Cache Nodes ................................................................................................................ 4 Cache Cluster ............................................................................................................... 4 Cache Parameter Groups ............................................................................................... 4 Cache Replication Groups .............................................................................................. 4 Security ....................................................................................................................... 5 Supported Operations ............................................................................................................ 5 Cache Cluster Operations ............................................................................................... 5 Cache Node Parameter Operations .................................................................................. 5 Cache Replication Group Operations (Redis only) ............................................................... 6 Accessing Amazon ElastiCache ............................................................................................... 6 Regions and Endpoints .................................................................................................. 6 Supported Regions ................................................................................................................ 6 Getting Started with Amazon ElastiCache .......................................................................................... 8 Step 1: Before You Begin ........................................................................................................ 8 Step 2: Launch a Cluster ........................................................................................................ 8 Step 2: Launch a Memcached Cluster ............................................................................... 9 Step 2: Launch a Redis Cluster ...................................................................................... 12 Step 3: Authorize Access ...................................................................................................... 15 You Launched Your Cluster into EC2-VPC ........................................................................ 16 You Launched Your Cluster into EC2-Classic .................................................................... 17 Step 4: Connect to a Cluster Node .......................................................................................... 17 Step 4: Connect to a Memcached Node ........................................................................... 18 Step 4: Connect to a Redis Cluster ................................................................................. 19 Step 5: Delete Your Cache Cluster .......................................................................................... 21 Where Do I Go From Here? ................................................................................................... 21 Best Practices for Implementing Amazon ElastiCache ........................................................................ 22 Ensuring That You Have Sufficient Memory to Create a Redis Snapshot ........................................ 22 BGSAVE Process and Memory Usage ............................................................................ 22 Avoiding Running Out of Memory When Executing BGSAVE ............................................... 23 Fault Tolerance: AOF or Multi-AZ? .......................................................................................... 24 Enabling Redis AOF for Fault Tolerance ........................................................................... 24 Enabling Redis Multi-AZ as a Better Approach to Fault Tolerance ......................................... 24 Configuring Your ElastiCache Client for Efficient Load Balancing .................................................. 24 Consistent Hashing Using Java ...................................................................................... 25 Consistent Hashing Using PHP ...................................................................................... 25 Consistent Hashing Using .NET ..................................................................................... 25 ElastiCache Terminology and Concepts ........................................................................................... 26 Nodes ................................................................................................................................ 26 Node Considerations for Memcached .............................................................................. 27 Node Considerations for Redis ....................................................................................... 29 Reserved Nodes .......................................................................................................... 29 Replication Groups and Read Replicas (Redis) ......................................................................... 30 Primary Endpoint ......................................................................................................... 31 Creating a Replication Group ......................................................................................... 31 Adding a Redis Cache Cluster to a Replication Group ........................................................ 32 Multi-AZ with Redis Replication Groups ................................................................................... 32 Notes on Multi-AZ with Redis Replication Groups .............................................................. 32 Failure Scenarios and Multi-AZ Responses ...................................................................... 33 Enabling Redis Multi-AZ ................................................................................................ 35 API Version 2015-02-02 iii Amazon ElastiCache User Guide Backup and Restore for Redis Clusters .................................................................................... 38 Constraints ................................................................................................................. 39 Costs ......................................................................................................................... 39 Automatic Snapshots ................................................................................................... 39 Manual Snapshots ....................................................................................................... 39 Performance Impact of Snapshots .................................................................................. 40 Restoring From a Snapshot ........................................................................................... 40 Deleting Snapshots ...................................................................................................... 41 Clusters ............................................................................................................................. 41 Memcached