Why is the set type used by redis cleared every day?

Question

There is no survival time set for the key, but every morning I find that the data from the previous day has been lost. What is the reason? Asking for guidance

View key survival time

ttl ip_blacklist
(integer) -1

View the type of value

type ip_blacklist
set

View stored values

SMEMBERS ip_blacklist
1) "127.0.0.1"

You will find that ip_blacklist is empty the next day

Answer 1

Is there no persistence, resulting in data loss

Answer 2

Is it because Redis stores too many things and the original values ​​​​are cleared?