Suppose I have [Slave IP Address] which is the slave of [Master IP Address].
Now my master server has been shut down, and I need to set this slave to be master MANUALLY (WITHOUT using sentinel automatic failover, WITH redis command).
Is it possible doing this without restarting the redis service ? (and losing all the cached data)
it depends, if you are in a cluster you will be better using the fail over. You will need to use the force option in the command
http://redis.io/commands/cluster-failover
use
SLAVEOF NO ONE
to promote a slave to masterhttp://redis.io/commands/slaveof