Foreword

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When we use mysql or other data, we will always encounter a large amount of disk space occupied by the database, resulting in insufficient disk space, which causes other problems (for example, the database cannot be started after restarting; the database cannot write data, etc.).
To solve this problem, the method is to delete some unnecessary files in the database. The mysql database occupies a lot of disk space is generally binlog log, because it records the changes in the data in the database, so it will continue to grow over time, the significance of its existence is to facilitate the data according to the log later Time or location based recovery and error handling.

The following describes the solution to solve the mysql database takes up a lot of disk space.

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Solution

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[Method 1] Manually delete

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[1] Check if the mysql binlog log is too large

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Due to the installation version or installation mode of mysql, the location or log name of the binlog log is different. You need to check the log size according to your own situation.
(general location is /var/lib//mysql/ or /usr/local/mysql/var/)

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<1>View

cd /mysql/data/
du -sh *

The figure above shows the location of the actual binlog log. As can be seen from the above figure, it is true that the mysql binlog log is too large, taking up disk space.

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[2] Delete log file

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There are two situations

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Case 1: The database is not master

<1> Delete log

Executed in the database:
reset master;

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If the database has master-slave, you can also use this command, but it is easy to cause master-slave synchronization to fail.

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Case 2: The database has been mastered

<1>View which file is the main library and the binlog that each slave library is using.

show master status;

show slave status\G;

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<2> Delete all binary logs in the log index before or before the specified log sequence number

purge master logs to’mysql-bin.000003’;
purge master logs before’2018-08-29 12:00:00’;

Note:
Cannot delete the binlog being used
Time and file name cannot be written incorrectly (depending on your own situation)

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[3] difference between reset master and purge binary logs

Reset master: Delete all binglog log files, clear the log index file, and restart the new log file.
purge binary logs: delete logs based on a certain point in time

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[Method 2] The system periodically deletes the binlog file.

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<1>View the current log save days
show variables like ‘expire_logs_days’;

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<2>Set a binlog that only keeps 3 days

(Temporary, restart mysql this parameter will fail)
set global expire_logs_days = 3;

(Permanent, added in my.cnf, effective after restart),
expire_logs_days = 3

Note:
The default value is 0, which means "auto delete is not enabled"
The expiration time should be set appropriately

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[Method 3] Disable binlog

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If you use master-slave, disable this operation

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<1> Comment out the following in my.cnf

#log-bin=mysql-bin
#binlog_format=mixed

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<2> restart mysql

systemctl restart mysql (centos 7)
/etc/init.d/mysql restart (centos 6)