Is it safe to delete mysql-bin files?

I have MM Replication in mysql, and I want to squeeze some free space in the box be deleting unnecessary files, I came across these mysql-bin files inside /var/db/mysql/ There are hundreds of those files like mysql-bin.000123, mysql-bin.000223 etc. I have checked the mysql replication by doing show master status and show slave status they are using some mysql-bin files at certain positions, but I guess all the other bin files are leftovers which will not be used anymore. In this case is it safe to delete all those mysql-bin files except the ones that replication is currently pointing at ?

If it is safe to delete, then is there anything I could do to automatically delete those files once they are not in use ?

Please do not just delete them in the OS.

You need to let mysqld do that for you. Here is how mysqld manages it:

The file mysql-bin.[index] keeps a list of all binary logs mysqld has generated and auto-rotated. The mechanisms for cleaning out the binlogs in conjunction with mysql-bin.[index] are:

PURGE BINARY LOGS TO 'binlogname';
PURGE BINARY LOGS BEFORE 'datetimestamp';

These will clear all binary logs before the binlog or timestamp you just specified.

For example, if you run

PURGE BINARY LOGS TO 'mysql-bin.000223';

this will erase all binary logs before mysql-bin.000223.

If you run

PURGE BINARY LOGS BEFORE DATE(NOW() - INTERVAL 3 DAY) + INTERVAL 0 SECOND;

this will erase all binary logs before midnight 3 days ago.

If you want to have binlog rotated away automatically and keep 3 days woth, simply set this:

mysql> SET GLOBAL expire_logs_days = 3;

then add this to /etc/my.cnf

[mysqld]
expire_logs_days=3

and mysqld will delete them logs for you
SHOW SLAVE STATUS\G

This is critical. When you run SHOW SLAVE STATUS\G, you will see two binary logs from the Master:

• Master_Log_File

• Relay_Master_Log_File

When replication has little or no lag these are usually the same value. When there is a lot of replication lag, these values are different. Just to make it simple, choose whatever Relay_Master_Log_File is, and go back to the Master and run

PURGE BINARY LOGS TO 'Whatever Relay_Master_Log_File Is';

That way, replication is not interrupted.

StackExchange Database Administrators Q#41050, answer score: 224