expire_logs_days ignored in my.cnf

Mysql (community) Version 8.0.17-1.sles12 - OpenSUSE tumbleweed 2019.10.02

mysql> SET GLOBAL expire_logs_days = 4;
ERROR 3683 (HY000): The option expire_logs_days and binlog_expire_logs_seconds
cannot be used together. Please use binlog_expire_logs_seconds to set the expire
time (expire_logs_days is deprecated)

..

Facts From Your Question

• Binary Logs cannot rotate out
• You said you can run PURGE BINARY LOGS

Here is my Working Theory

Since you can erase binary logs using PURGE BINARY LOGS;, I have two places for you to look that you have not mentioned

PLACE #1 : mysql-bin.index

This file contains the location of all binary logs. When expire_logs_days is set, mysqld will open this text file, check the datetime stamps in each file until it encounters a binary logs that has a timestamp less than NOW() - INTERVAL expire_logs_days DAY).

The binary logs in mysql-bin.index is expected to be numerically consecutive. If the binary logs are not numerically consecutive, log rotation is disabled.

PLACE #2 : /var/log/mysql folder

According to your my.cnf, This folder holds all the binary logs.

Here are 2 questions:

1. Are there any binary logs in /var/log/mysql that are not numerically consecutive?
2. Are there any binary logs in /var/log/mysql that are NOT IN mysql-bin.index ?

Why would these situations come up ?

Sometimes, people delete binary logs in the OS. This can throw off mysqld since mysqld uses mysql-bin.index to internally track the existence of binary logs. Simply deleting binary logs with rm -f logically breaking the log rotation mechanism as mysqld knows it.

RECOMMENDATION

If either or both are the case, you can clean this up as follows:

mysql -ANe"RESET MASTER"
service mysql stop
cd /var/log/mysql
rm -f mysql-bin.*
cd
service mysql start

After this, you should have a brand spanking new binary log setup.

Give it a Try !!!