Aurora MySQL: how do I keep binlogs around after reboot?

Question

We have a request to enable binlogs on an Aurora MySQL instance and to keep those logs around for a certain amount of time. To test, we enabled binlogging with binlog_format=ROW and set our retention time to 1 hour.

call mysql.rds_set_configuration('binlog retention hours', 1);

However, we are seeing inconsistent behavior when we reboot the instance. A new binlog gets created and the old one sometimes drops after only a couple of minutes. It was my understanding that setting the retention hours would keep the old file(s) around for an hour.

There is also the global config expire_logs_days=0, would that affect keeping the old file(s) around?

Answer 1

If writes to the RDS Instance had not occurred for over an hour, all binlogs whose timestamp is older than an hour must disappear after mysqld starts up in the RDS Instance.

If you want the binlogs to stay longer, raise the retention hours to 4 (or higher)

call mysql.rds_set_configuration('binlog retention hours', 4);

just before reboot.

Don't lower it right away after the reboot. Otherwise, those binlogs whose timestamp is older than an hour would disappear just the same.