AWS ElastiCache
本文缩写（英文全称与中文含义）
| 缩写 | 英文全称／名称 | 中文含义 |
|---|---|---|
| ACL | Access Control List | 访问控制列表 |
| AWS | Amazon Web Services | 亚马逊云服务 |
| KMS | Key Management Service | 密钥管理服务 |
| RDB | Redis Database snapshot | Redis 数据库快照格式 |
| RDS | Relational Database Service | AWS 关系型数据库服务 |
| S3 | Simple Storage Service | AWS 对象存储服务 |
| SNS | Simple Notification Service | AWS 消息通知服务 |
| TTL | Time To Live | 存活时间；具体指缓存有效期或记录过期时间 |
Guides#
1. Important Points#
Amazon ElastiCache for Valkey 是 managed in-memory data store。迁移前首先确认它只是可重建 cache，还是保存 session、token、rate limit、lock、queue 或其他不可丢业务状态。
rebuildable cache:
prefer creating a new cache and warming it from the source of truth
stateful Valkey workload:
requires backup/restore or application-level migration semantics
TTL, ordering, locks, duplicate delivery, and cutover must be designed2. Migration Options#
| Requirement | Recommended option | Important limitation |
|---|---|---|
| 同账号跨 Region managed replication | ElastiCache Global Datastore | 不解决跨 AWS account |
| 跨账号跨 Region、允许停机 | Backup/RDB -> S3 -> destination seed | 停机包含 snapshot、copy、restore、验证和切换 |
| 跨账号低停机、可重建 cache | Create target -> warm from source of truth -> cut over | 不复制无权威来源的临时状态 |
| 跨账号低停机、状态不可丢 | Application dual-write or durable event replay | ElastiCache 本身没有跨账号 Global Datastore |
Global Datastore 是跨 Region 功能，不是 RDS 风格的跨账号 snapshot sharing。ElastiCache native snapshot 没有直接的跨账号分享流程；停机迁移通常通过 S3 中的 RDB seed objects 连接两个账号和 Region。
3. Snapshot Scope#
Valkey backup captures cache data, but does not recreate the complete AWS resource configuration:
included as data:
keys and values
supported data types
expiration metadata stored in RDB
must be recreated:
replication group topology
node type and replica count
subnet group and security groups
parameter group
users, user groups, ACL and auth settings
KMS and transit encryption settings
CloudWatch alarms, SNS notifications and tags
endpoints and application configurationTTL continues to elapse during downtime. RDB is not a way to pause expiration permanently; keys that expire before or during restore may no longer exist when the target becomes available.