Mysql數據庫二進制日志的管理

如果配置了log_bin參數，則需要配置expire_logs_days參數指定二進制日志保留時間，不然磁盤空間早晚會被日志占滿的。如果之前沒有配置，則配置步驟如下：

1、查看當前配置
(root@localhost)[(none)] show global variables like 'log_bin';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_bin       | ON    |
+---------------+-------+
1 row in set (0.02 sec)

(root@localhost)[(none)] show global variables like 'expire_logs_days';
+------------------+-------+
| Variable_name    | Value |
+------------------+-------+
| expire_logs_days | 0     |
+------------------+-------+
1 row in set (0.00 sec)

(root@localhost)[(none)] show global variables like 'max_binlog_size';
+-----------------+------------+
| Variable_name   | Value      |
+-----------------+------------+
| max_binlog_size | 1073741824 |
+-----------------+------------+
1 row in set (0.00 sec)

(root@localhost)[(none)] show binary logs;
+------------------+-----------+
| Log_name         | File_size |
+------------------+-----------+
| mysql-bin.000001 |       614 |
| mysql-bin.000002 |      1595 |
| mysql-bin.000003 | 445747850 |
+------------------+-----------+
3 rows in set (0.02 sec)

[root@dbrac16 ~]# ll /usr/local/mysql/data/mysql-bin*
-rw-r----- 1 mysql mysql       614 May 11 10:06 /usr/local/mysql/data/mysql-bin.000001
-rw-r----- 1 mysql mysql      1595 May 17 09:45 /usr/local/mysql/data/mysql-bin.000002
-rw-r----- 1 mysql mysql 445747850 May 19 14:28 /usr/local/mysql/data/mysql-bin.000003
-rw-r----- 1 mysql mysql       117 May 17 11:16 /usr/local/mysql/data/mysql-bin.index

2、查看slave狀態
[root@dbrac17 ~]# mysql -uroot -p123456 -e "show slave status\G" | grep Master_Log_File
mysql: [Warning] Using a password on the command line interface can be insecure.
              Master_Log_File: mysql-bin.000003
        Relay_Master_Log_File: mysql-bin.000003

3、手動清除過期的日志
如果堆積的日志太多，可以先執行這一步，清理掉一部分日志。
(root@localhost)[(none)] purge master logs before '2017-05-17 00:00:00';
Query OK, 0 rows affected (0.15 sec)

(root@localhost)[(none)] show binary logs;
+------------------+-----------+
| Log_name         | File_size |
+------------------+-----------+
| mysql-bin.000002 |      1595 |
| mysql-bin.000003 | 445747850 |
+------------------+-----------+
2 rows in set (0.00 sec)

4、配置參數
[root@dbrac16 ~]# cat /etc/my.cnf | grep expire_logs_days
expire_logs_days = 3

修改參數文件，設置日志保留3天，需要重啟才能生效。
直接設置，立即生效。
(root@localhost)[(none)] set global expire_logs_days=3;
Query OK, 0 rows affected (0.00 sec)

觸發過期日志清除操作。
(root@localhost)[(none)]  flush logs;
Query OK, 0 rows affected (0.04 sec)

(root@localhost)[(none)] show binary logs;
+------------------+-----------+
| Log_name         | File_size |
+------------------+-----------+
| mysql-bin.000003 | 445747897 |
| mysql-bin.000004 |       201 |
+------------------+-----------+
3 rows in set (0.00 sec)