How do I move a redis database from one server to another?

Question

I currently have a live redis server running on a cloud instance and I want to migrate this redis server to a new cloud instance and use that instance as my new redis server

Answer 1

Key elements of a zero-downtime migration is:

• replication (http://redis.io/commands/SLAVEOF)
• possibility to write into a slave during application switching (CONFIG SET slave-read-only no)

In short:

1. setup a target redis (empty) as slave of a source redis (with your data)
2. wait for replication finish
3. permit writes to a target redis (which is currently slave)
4. switch your apps to a target redis
5. wait for finish datastream from master to slave
6. turn a target redis from master to slave

Additionally redis have options which allows to disable a source redis to accept writes right after detaching a target:

• min-slaves-to-write
• min-slaves-max-lag

This topic covered by

• http://redis.io/topics/admin#upgrading-or-restarting-a-redis-instance-without-downtime

Very good explanation from RedisLabs team https://redislabs.com/blog/real-time-synchronization-tool-for-redis-migration (use web.archive.org)

And even their interactive tool for migrate: https://github.com/RedisLabs/redis-migrate