Middleware Layer Migration Solutions

Cache middleware and message middleware are commonly used in enterprises' business. The middleware temporarily stores data, and generally the data does not need to be migrated. The cutover can be performed only after messages in the middleware message queues are consumed. This ensures consistency between the source and destination data. If the middleware cache data is stored persistently in databases, the data also needs to be migrated. This section describes how to design migration solutions for different types of middleware.

• Redis migration solution

• Application scenarios of Redis

  A Redis instance can be used as a cache or database. The following table lists the migration solutions for Redis in the two scenarios.

  Table 1 Migration solutions for Redis in different scenarios

  Redis Application Scenario	Migration Method
  Redis caches data.	During service cutover, you can determine which migration solution to use based on the database performance to prevent the Redis database from breaking down. Solution 1: Do not migrate the Redis cache data. Preload it. Solution 2: Migrate the cache data using the Redis migration solution.
  Redis stores data persistently.	Migrate persistent data using the Redis migration solution.

• Redis migration solution

  Table 2 Redis migration solution

  Migration Solution	Migration Method	Description	Scenario
  (Recommended) DCS migration tool	Full and incremental migration	Short service downtime at the source, simple operations, and online real-time incremental synchronization	Self-hosted Redis is available at the source or Redis instances from other cloud vendors are migrated to Huawei Cloud DCS.
  RDB/AOF file backup and restoration	Full migration	Complex offline migration, long service downtime at the source for RDB/AOF file creation, and unavailability of incremental data synchronization	All

• Message middleware migration solution

• Cutover scenarios for the message middleware

  Table 3 Cutover scenarios for the message middleware

  Applicable Product	Cutover Window	Migration Method
  Kafka RabbitMQ RocketMQ ActiveMQ	Sufficient	The cutover time is sufficient. Messages can be used up within the time as estimated and do not need to be migrated.
  	Limited	The cutover time is limited. Messages cannot be used up within the time as estimated and need to be migrated based on the message middleware migration solution.

• Message middleware migration solution

  Table 4 Message middleware migration solution

  Migration Solution	Migration Method	Description	Scenario
  Open-source MirrorMaker 2.0	Full + Incremental	1. Complex deployment and operations 2. Synchronization of offset of a consumption queue	All
  Huawei Cloud SmratConnect	Full + Incremental	1. Simple operations on the GUI 2. Synchronization of offset of a consumption queue	Migration of on-premises Kafka or cloud services to Huawei Cloud Kafka