Why is all data removed from Redis?

Question

Redis

Everything is removed from the radish after a few hours. When the connection breaks, everything is also erased. I'm not an expert in it, I'm using it for the first time; set according to this instruction:
https://bit.ly/36bN0zR
What needs to be done so that the data is always in place? I just installed it and made redis-server and redis-cli command. Maybe something else is needed? And extra. the question is - so that the data remains even after the server / reconnect is rebooted, can this be done?

Answer 1

Documentation section on how to persist data
https://redis.io/topics/persistence