MySQL 备份和恢复（一）mysqldump

备份方式：
热备：不中断服务
温备：备份过程中不可写，要加读锁
冷备：需要停掉服务

备份策略一：mysqldump + binlog 完全备份 + 增量，用mysqldump定期全备，每天（根据实际情况来）备份二进制日志.
mysqldump类似于一个mysql的客户端，所以用mysqldump备份时，mysql服务要启动起来，常用参数：
-u username | --user=username 指定备份的用户

-p password | --password=password

-h host | --host=host

-p port | --port=port

-A --all-databases 备份所有数据库

-B --databases db_name 选择要备份的数据库

-C --compress 启用压缩

-d --no-data 备份空库，不备份数据

-E --events 同时备份事件调度器代码

-F --flush-logs 备份前先滚动日志

--ignore-tables db_name.tb_name 指定哪些表不必备份

--lock-tables 要备份一张表时，备份前先锁定表

-x --lock-all-tables 备份前锁定所有库的所有表

--single-transaction 为备份创建一个大事务，基于快照原理实现MVCC对InnoDB热备，开启此选项则不用-x，只对InnoDB支持事务的表才可保证一致性

--master-data = 0|1|2 在复制架构中，指定如何处理配置主从服务器的语句如CHANGE MASTER TO statement，值为2记录但是是注释掉，应用时不生效，值为1记录不注释，应用时生效, 0为不启用。

过程简单演示：

[root@node1 ~]# mysqldump -uroot -pmypass --all-databases --master-data=2 --lock-all-tables --flush-logs > /backup/full_db_`date +%F`.sql
[root@node1 ~]# ls /backup/full_db_2014-07-29.sql -l
-rw-r--r--. 1 root root 523830 Jul 29 11:08 /backup/full_db_2014-07-29.sql

MariaDB [hellodb]> SELECT * FROM scores;
+----+-------+----------+-------+
| ID | StuID | CourseID | Score |
+----+-------+----------+-------+
|  1 |     1 |        2 |    77 |
|  2 |     1 |        6 |    93 |
|  3 |     2 |        2 |    47 |
|  4 |     2 |        5 |    97 |
|  5 |     3 |        2 |    88 |
|  6 |     3 |        6 |    75 |
|  7 |     4 |        5 |    71 |
|  8 |     4 |        2 |    89 |
|  9 |     5 |        1 |    39 |
| 10 |     5 |        7 |    63 |
| 11 |     6 |        1 |    96 |
| 12 |     7 |        1 |    86 |
| 13 |     7 |        7 |    83 |
| 14 |     8 |        4 |    57 |
| 15 |     8 |        3 |    93 |
+----+-------+----------+-------+
15 rows in set (0.00 sec)

MariaDB [hellodb]> DELETE FROM scores WHERE ID>10 AND ID<=14;
Query OK, 4 rows affected (0.08 sec)

MariaDB [hellodb]> SELECT * FROM hellodb.scores;
+----+-------+----------+-------+
| ID | StuID | CourseID | Score |
+----+-------+----------+-------+
|  1 |     1 |        2 |    77 |
|  2 |     1 |        6 |    93 |
|  3 |     2 |        2 |    47 |
|  4 |     2 |        5 |    97 |
|  5 |     3 |        2 |    88 |
|  6 |     3 |        6 |    75 |
|  7 |     4 |        5 |    71 |
|  8 |     4 |        2 |    89 |
|  9 |     5 |        1 |    39 |
| 10 |     5 |        7 |    63 |
| 15 |     8 |        3 |    93 |
+----+-------+----------+-------+
11 rows in set (0.00 sec)

/* 这里把二进制日志关掉插入些数据，下面会把二进制再打开，再插入些数据 */
MariaDB [hellodb]> SET sql_log_bin=0;
Query OK, 0 rows affected (0.00 sec)

MariaDB [hellodb]> SHOW VARIABLES LIKE '%SQL_LOG_BIN%';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| sql_log_bin   | OFF   |
+---------------+-------+
1 row in set (0.00 sec)

MariaDB [hellodb]> SHOW MASTER STATUS;
+------------------+----------+--------------+------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000006 |      495 |              |                  |
+------------------+----------+--------------+------------------+

MariaDB [hellodb]> INSERT INTO scores (StuID,CourseID,Score) VALUES (3,3,3),(4,4,4),(5,5,5);
Query OK, 3 rows affected (0.06 sec)
Records: 3  Duplicates: 0  Warnings: 0

/* 这里顺带看下二进制日志位置在495 */
MariaDB [hellodb]> SHOW MASTER STATUS;
+------------------+----------+--------------+------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000006 |      495 |              |                  |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)

MariaDB [hellodb]> SET sql_log_bin=1;
Query OK, 0 rows affected (0.00 sec)

MariaDB [hellodb]> SHOW VARIABLES LIKE 'sql_log_bin';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| sql_log_bin   | ON    |
+---------------+-------+
1 row in set (0.00 sec)

/* 把binlog打开后再插入一些数据 */
MariaDB [hellodb]> INSERT INTO scores (StuID,CourseID,Score) VALUES (10,11,12),(13,14,15);
Query OK, 2 rows affected (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 0

/* LAST_INSERT_ID()这个函数可以查看有AUTO_INCREMENT属性的字段上次长到哪里了 */
MariaDB [hellodb]> SELECT LAST_INSERT_ID();
+------------------+
| LAST_INSERT_ID() |
+------------------+
|               19 |
+------------------+
1 row in set (0.00 sec)

/* 仔细看一下下面的查询结果我们新插入的数据并没有按顺序在ID=15后面，而是依次被存入到之前删除的行释放后的存储空间里了 */
MariaDB [hellodb]> SELECT * FROM scores;
+----+-------+----------+-------+
| ID | StuID | CourseID | Score |
+----+-------+----------+-------+
|  1 |     1 |        2 |    77 |
|  2 |     1 |        6 |    93 |
|  3 |     2 |        2 |    47 |
|  4 |     2 |        5 |    97 |
|  5 |     3 |        2 |    88 |
|  6 |     3 |        6 |    75 |
|  7 |     4 |        5 |    71 |
|  8 |     4 |        2 |    89 |
|  9 |     5 |        1 |    39 |
| 10 |     5 |        7 |    63 |
| 19 |    10 |       11 |    12 |
| 18 |     5 |        5 |     5 |
| 17 |     4 |        4 |     4 |
| 16 |     3 |        3 |     3 |
| 15 |     8 |        3 |    93 |
| 20 |    13 |       14 |    15 |
+----+-------+----------+-------+
16 rows in set (0.00 sec)

/* 删除hellodb数据库，模拟数据库崩溃 */
MariaDB [(none)]> DROP DATABASE hellodb;
Query OK, 9 rows affected (0.47 sec)

MariaDB [(none)]> SHOW DATABASES;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mydb               |
| mysql              |
| performance_schema |
| test               |
+--------------------+
5 rows in set (0.01 sec)

/* 因为全备时用了--flush-logs选项，所以只要备份最后一个二进制日志就可以了 */
cp /mydata/data/mysql-bin.000006 /backup/
[root@node1 data]# cd /backup/

/* 因为执行了DROP DATABASE语句，所以恢复时把这个语句之前的binlog应用就可以了 */
[root@node1 backup]# mysqlbinlog 'mysql-bin.000006' | grep 'DROP DATABASE' -B 15
#140729 13:59:59 server id 1  end_log_pos 594 	Intvar
SET INSERT_ID=19/*!*/;
# at 594
#140729 13:59:59 server id 1  end_log_pos 730 	Query	thread_id=25	exec_time=0	error_code=0
SET TIMESTAMP=1406613599/*!*/;
INSERT INTO scores (StuID,CourseID,Score) VALUES (10,11,12),(13,14,15)
/*!*/;
# at 730
#140729 13:59:59 server id 1  end_log_pos 802 	Query	thread_id=25	exec_time=0	error_code=0
SET TIMESTAMP=1406613599/*!*/;
COMMIT
/*!*/;
# at 802
#140729 14:15:57 server id 1  end_log_pos 889 	Query	thread_id=26	exec_time=0	error_code=0
SET TIMESTAMP=1406614557/*!*/;
DROP DATABASE hellodb

/* 找到位置后把需要的日志导出来 */
[root@node1 backup]# mysqlbinlog 'mysql-bin.0000061' --stop-position=730 > /backup/inr-001.sql

/* 恢复完全备份,这里直接是全库备份了，当然也可以根据需要对单库单表备份 */
[root@node1 backup]# mysql < /backup/full_db_2014-07-29.sql

/* 恢复后可以看到hellodb已经恢复回来，数据内容也都在了 */
MariaDB [(none)]> SHOW DATABASES;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| hellodb            |
| mydb               |
| mysql              |
| performance_schema |
| test               |
+--------------------+
6 rows in set (0.00 sec)

MariaDB [(none)]> USE hellodb;
Database changed
MariaDB [hellodb]> SELECT * FROM scores;
+----+-------+----------+-------+
| ID | StuID | CourseID | Score |
+----+-------+----------+-------+
|  1 |     1 |        2 |    77 |
|  2 |     1 |        6 |    93 |
|  3 |     2 |        2 |    47 |
|  4 |     2 |        5 |    97 |
|  5 |     3 |        2 |    88 |
|  6 |     3 |        6 |    75 |
|  7 |     4 |        5 |    71 |
|  8 |     4 |        2 |    89 |
|  9 |     5 |        1 |    39 |
| 10 |     5 |        7 |    63 |
| 11 |     6 |        1 |    96 |
| 12 |     7 |        1 |    86 |
| 13 |     7 |        7 |    83 |
| 14 |     8 |        4 |    57 |
| 15 |     8 |        3 |    93 |
+----+-------+----------+-------+
15 rows in set (0.00 sec)

/* 上面删除数据的时候忘备份一份二进制日志了，图省事，手动造一下 */
[root@node1 backup]# mysqlbinlog 'mysql-bin.000006' | grep --color 'DELETE FROM' -C 5
/*!*/;
# at 316
#140729 11:17:42 server id 1  end_log_pos 423 	Query	thread_id=25	exec_time=0	error_code=0
use `hellodb`/*!*/;
SET TIMESTAMP=1406603862/*!*/;
DELETE FROM scores WHERE ID>10 AND ID<=14
/*!*/;
# at 423
#140729 11:17:42 server id 1  end_log_pos 495 	Query	thread_id=25	exec_time=0	error_code=0
SET TIMESTAMP=1406603862/*!*/;
COMMIT

[root@node1 backup]# mysqlbinlog 'mysql-bin.000006' --stop-position=423 > /backup/inc-001.sql
[root@node1 backup]# mysqlbinlog 'mysql-bin.000006' --start-position=423 --stop-position=730 > /backup/inc-002.sql
[root@node1 backup]# mysql < inc-001.sql
/* 恢复到时间点一，ID 11到14被删除 */
MariaDB [(none)]> SELECT * FROM hellodb.scores;
+----+-------+----------+-------+
| ID | StuID | CourseID | Score |
+----+-------+----------+-------+
|  1 |     1 |        2 |    77 |
|  2 |     1 |        6 |    93 |
|  3 |     2 |        2 |    47 |
|  4 |     2 |        5 |    97 |
|  5 |     3 |        2 |    88 |
|  6 |     3 |        6 |    75 |
|  7 |     4 |        5 |    71 |
|  8 |     4 |        2 |    89 |
|  9 |     5 |        1 |    39 |
| 10 |     5 |        7 |    63 |
| 15 |     8 |        3 |    93 |
+----+-------+----------+-------+
11 rows in set (0.00 sec)

/* 恢复到时间点二，插入了一些数据后，哎我去，咋的我插入了那老些数据就剩这一点了捏，这正是
sql-bin-log变量起作用了，因为当时有几条数据是关闭了二进制日志做的操作，所以未被记录到
binlog，自然恢复过来的数据中也就木有了，这点在做恢复时是非常有必要的，因为恢复时的操作都
是之前做过的，关闭二进制日志可以避免不必要的开销。*/
[root@node1 backup]# mysql < inc-002.sql
MariaDB [(none)]> SELECT * FROM hellodb.scores;
+----+-------+----------+-------+
| ID | StuID | CourseID | Score |
+----+-------+----------+-------+
|  1 |     1 |        2 |    77 |
|  2 |     1 |        6 |    93 |
|  3 |     2 |        2 |    47 |
|  4 |     2 |        5 |    97 |
|  5 |     3 |        2 |    88 |
|  6 |     3 |        6 |    75 |
|  7 |     4 |        5 |    71 |
|  8 |     4 |        2 |    89 |
|  9 |     5 |        1 |    39 |
| 10 |     5 |        7 |    63 |
| 20 |    13 |       14 |    15 |
| 19 |    10 |       11 |    12 |
| 15 |     8 |        3 |    93 |
+----+-------+----------+-------+
13 rows in set (0.00 sec)