Official doc: https://github.com/sidekiq/sidekiq/wiki/Using-Redis
Sidekiq uses Redis to store Sidekiq Jobs.
Sidekiq Client (as of v6.4.1), you cannot use a different Redis. It will always use the redis from Sidekiq Server.
sidekiq_redis_pool = ConnectionPool.new(...) Sidekiq.configure_server do |config| config.redis = sidekiq_redis_pool end
If you are pass in a Redis Pool to Sidekiq Server like above, you need
to make sure size of your Redis pool is at least the Sidekiq concurrency + five more connections:
ConnectionPool.new(size: Sidekiq.options[:concurrency] + 5) do Redis.new(url: ENV["SIDEKIQ_REDIS_URL"]) end
(Redis) Cluster is for caching and similar workloads that can scale horizontally. That is not Sidekiq.