Redis Upgrade from 3.0.7 to 5

Question

I have plenty of Sentinel and Cluster servers running 3.0.7 and need to upgrade to 5. I cannot afford downtime. Can someone please advice me how to do it? Some DBs are so big that the servers cannot allocate a new/second instance in case of the best solution here is lunching a new Redis 5 on the same server and set it as slave of the 3.0.7.

1) Can I just go directly from 3.2 to 5 or do I need jump into 4 first?

2) Reading from here that need a massive restart when upgrading from 3.3 to 4. Any way to avoid downtime? How to reestablish the original cluster data? Backup and restore?

Any advice is welcome.

Answer 1

You can change redis 5.0 cluster bus protocol to make it compatible with 3.0.7.

Redis 5.0' cluster bus protocol is 1 while redis 3.0.7 has cluster bus protocol is 0.

You must pay attention to the following 2 differences:

1. Cluster bus protocol 1 supports module message while protocol 0 does not.
2. Cluster bus protocol 1's ping message has an extra 'cport' field.