MySQL Study之--MySQL 备份

MySQL Study之--MySQL 备份

一、备份的目的

做灾难恢复：对损坏的数据进行恢复和还原

需求改变：因需求改变而需要把数据还原到改变以前

测试：测试新功能是否可用

二、备份需要考虑的问题

可以容忍丢失多长时间的数据；

恢复数据要在多长时间内完；

恢复的时候是否需要持续提供服务；

恢复的对象，是整个库，多个表，还是单个库，单个表。

三、备份的类型

1、根据是否需要数据库离线

冷备（cold backup）：需要关mysql服务，读写请求均不允许状态下进行；

温备（warm backup）： 服务在线，但仅支持读请求，不允许写请求；

热备（hot backup）：备份的同时，业务不受影响。

注：

1、这种类型的备份，取决于业务的需求，而不是备份工具

2、MyISAM支持热备（mysqlhotcopy），InnoDB支持热备（ibbackup、xtrabackup）

2、根据要备份的数据集合的范围

完全备份：full backup，备份全部字符集。

增量备份: incremental backup 上次完全备份或增量备份以来改变了的数据，不能单独使用，要借助完全备份，备份的频率取决于数据的更新频率。

差异备份：differential backup 上次完全备份以来改变了的数据。

建议的恢复策略：

完全+增量+二进制日志

完全+差异+二进制日志

3、根据备份数据或文件

物理备份：直接备份数据文件

优点：

备份和恢复操作都比较简单，能够跨mysql的版本，

恢复速度快，属于文件系统级别的

建议：

不要假设备份一定可用，要测试

mysql>check tables；检测表是否可用

逻辑备份: 备份表中的数据和代码

优点：

恢复简单、

备份的结果为ASCII文件，可以编辑

与存储引擎无关

可以通过网络备份和恢复

缺点：

备份或恢复都需要mysql服务器进程参与

备份结果占据更多的空间，

浮点数可能会丢失精度

还原之后，缩影需要重建

四：备份的对象

1、 数据；

2、配置文件；

3、代码：存储过程、存储函数、触发器

4、OS相关的配置文件

5、复制相关的配置

6、二进制日志

逻辑备份工具：

一、表的导出

SELECT INTO…OUTFILE语句把表数据导出到一个文本文件中，并用LOAD DATA …INFILE语句恢复数据。但是这种方法只能导出或导入数据的内容，不包括表的结构，如果表的结构文件损坏，则必须先恢复原来的表的结构。

一、SELECT INTO…OUTFILE语法：

select * from Table into outfile '/路径/文件名'

fields terminated by ','

enclosed by '"'

lines terminated by '\r\n'

fields子句：在FIELDS子句中有三个亚子句：TERMINATED BY、 [OPTIONALLY] ENCLOSED BY和ESCAPED BY。如果指定了FIELDS子句，则这三个亚子句中至少要指定一个。

（1）TERMINATED BY用来指定字段值之间的符号，例如，“TERMINATED BY ','”指定了逗号作为两个字段值之间的标志。

（2）ENCLOSED BY子句用来指定包裹文件中字符值的符号，例如，“ENCLOSED BY ' " '”表示文件中字符值放在双引号之间，若加上关键字OPTIONALLY表示所有的值都放在双引号之间。

（3）ESCAPED BY子句用来指定转义字符，例如，“ESCAPED BY '*'”将“*”指定为转义字符，取代“\”，如空格将表示为“*N”。

● LINES子句：在LINES子句中使用TERMINATED BY指定一行结束的标志，如“LINES TERMINATED BY '?'”表示一行以“?”作为结束标志。

案例：

[root@rh64 ~]# mysql -u root -p

Enter password:

Welcome to the MySQL monitor. Commands end with ; or \g.

Your MySQL connection id is 1

Server version: 5.6.25-73.1 Percona Server (GPL), Release 73.1, Revision 07b797f

Copyright (c) 2009-2015 Percona LLC and/or its affiliates

Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>

mysql> show databases;

+--------------------+

| Database |

+--------------------+

| information_schema |

| mysql |

| performance_schema |

| prod |

| test |

+--------------------+

5 rows in set (0.04 sec)

mysql> use prod;

Reading table information for completion of table and column names

You can turn off this feature to get a quicker startup with -A

Database changed

mysql> show tables;

+----------------+

| Tables_in_prod |

+----------------+

| t1 |

| t2 |

| t3 |

+----------------+

3 rows in set (0.00 sec)

mysql> insert into t2 select * from t1 order by id limit 100;

Query OK, 100 rows affected (0.33 sec)

Records: 100 Duplicates: 0 Warnings: 0

mysql> commit;

Query OK, 0 rows affected (0.00 sec)

mysql> select count(*) from t2;

+----------+

| count(*) |

+----------+

| 100 |

+----------+

1 row in set (0.00 sec)

mysql> select * from t2 into outfile '/tmp/t2_1.bak';

Query OK, 100 rows affected (0.00 sec)

[root@rh64 ~]# cat /tmp/t2_1.bak

1 tom

1 tom

1 tom

1 tom

......

---默认字段之间是通过制表符（tab）进行分割的

mysql> select * from t2 into outfile '/tmp/t2_2.bak' fields terminated by ',' enclosed by '"';

Query OK, 100 rows affected (0.00 sec)

[root@rh64 ~]# cat /tmp/t2_2.bak

"1","tom"

"1","tom"

"1","tom"

......

---发现第一列为数值字段，也被添加了“”

mysql> select * from t2 into outfile '/tmp/t2_3.bak' fields terminated by ',' optionally enclosed by '"';

Query OK, 100 rows affected (0.00 sec)

[root@rh64 ~]# cat /tmp/t2_3.bak

1,"tom"

1,"tom"

1,"tom"

......

---发现第一列为数值字段，就没有添加了“”，只有字符型的字段有“”

二、表的导入

mysql> load data infile '/tmp/t2_1.bak' into table t2;

Query OK, 100 rows affected (0.06 sec)

Records: 100 Deleted: 0 Skipped: 0 Warnings: 0

mysql> select count(*) from t2;

+----------+

| count(*) |

+----------+

| 100 |

+----------+

1 row in set (0.00 sec)

mysql> load data infile '/tmp/t2_2.bak' into table t2 fields terminated by ',' enclosed by '"';

Query OK, 100 rows affected (0.07 sec)

Records: 100 Deleted: 0 Skipped: 0 Warnings: 0

mysql> select count(*) from t2;

+----------+

| count(*) |

+----------+

| 100 |

+----------+

1 row in set (0.00 sec)

案例：通过备份脚本备份

1、建立备份目录

[root@rh64 ~]# mkdir -p /data/mysql/backup

[root@rh64 ~]# chown -R mysql:mysql /data

[root@rh64 ~]# chmod -R 777 /data

2、授权用户

[root@rh64 ~]# /usr/bin/mysql -u root -p

Enter password:

Welcome to the MySQL monitor. Commands end with ; or \g.

Your MySQL connection id is 5

Server version: 5.6.25-73.1 Percona Server (GPL), Release 73.1, Revision 07b797f

Copyright (c) 2009-2015 Percona LLC and/or its affiliates

Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> grant all on prod.* to 'mysql'@'192.168.8.248' identified by 'oracle';

Query OK, 0 rows affected (0.00 sec)

---用户没有权限执行outfile，必须授予file权限

mysql> select * from t2 into outfile '/tmp/t2.txt';

ERROR 1045 (28000): Access denied for user 'root'@'192.168.8.248' (using password: YES)

mysql> select * from t2;

+------+------+

| id | name |

+------+------+

| 1 | tom |

| 1 | tom |

| 1 | tom |

| 1 | tom |

| 1 | tom |

| 1 | tom |

| 1 | tom |

授予file权限：

mysql> grant file on *.* to 'root'@'192.168.8.248' identified by 'oracle';

Query OK, 0 rows affected (0.00 sec)

备份脚本：

backup Script:

#!/bin/bash

#FileName:select_into_bak.sh

#Desc:Use select into outfile to backup db or tables

#Created By:fedoracle

#Date:2015/10/15




DB=prod

USER=mysql

PASSWD=oracle

HOST=192.168.8.248

BAK_DIR=/data/mysql/backup/$DB

DATE=`date "+%Y-%m-%d %H-%M-%S"`




[ -d "$BAK_DIR" ] || /bin/mkdir -p $BAK_DIR && /bin/chown mysql:mysql $BAK_DIR

/usr/bin/mysql -h$HOST -u$USER -p$PASSWD -e "show tables from $DB" | grep -v "Tables_in" > $BAK_DIR/tab.txt

for table in `cat $BAK_DIR/tab.txt`

do

/usr/bin/mysql -h$HOST -u$USER -p$PASSWD -e "select * from $DB.$table into outfile '"$BAK_DIR/$table".txt' character set utf8;"

done


cd $BAK_DIR

/bin/tar -czf "$DB-$DATE".tar.gz *.txt

/bin/rm -f *.txt

exit 0

在执行备份时，写出文件到备份目录下，需关闭系统selinux：

[root@rh64 ~]# su - mysql

[mysql@rh64 ~]$ cd /data/mysql/backup/

[mysql@rh64 backup]$ sh bak.sh

Warning: Using a password on the command line interface can be insecure.

Warning: Using a password on the command line interface can be insecure.

ERROR 1 (HY000) at line 1: Can't create/write to file '/data/mysql/backup/prod/t1.txt' (Errcode: 13 - Permission denied)

Warning: Using a password on the command line interface can be insecure.

ERROR 1 (HY000) at line 1: Can't create/write to file '/data/mysql/backup/prod/t2.txt' (Errcode: 13 - Permission denied)

Warning: Using a password on the command line interface can be insecure.

ERROR 1 (HY000) at line 1: Can't create/write to file '/data/mysql/backup/prod/t3.txt' (Errcode: 13 - Permission denied)

查看关闭selinux：

[mysql@rh64 backup]$ cat /etc/sysconfig/selinux

# This file controls the state of SELinux on the system.

# SELINUX= can take one of these three values:

# enforcing - SELinux security policy is enforced.

# permissive - SELinux prints warnings instead of enforcing.

# disabled - No SELinux policy is loaded.

SELINUX=enforcing

# SELINUXTYPE= can take one of these two values:

# targeted - Targeted processes are protected,

# mls - Multi Level Security protection.

SELINUXTYPE=targeted

[mysql@rh64 backup]$ su -

Password:

[root@rh64 ~]# vi /etc/sysconfig/selinux

# This file controls the state of SELinux on the system.

# SELINUX= can take one of these three values:

# enforcing - SELinux security policy is enforced.

# permissive - SELinux prints warnings instead of enforcing.

# disabled - No SELinux policy is loaded.

SELINUX=disabled

# SELINUXTYPE= can take one of these two values:

# targeted - Targeted processes are protected,

# mls - Multi Level Security protection.

SELINUXTYPE=targeted

~

"/etc/sysconfig/selinux" 13L, 457C written

关闭selinux：

[root@rh64 ~]# setenforce 0

[root@rh64 ~]# getenforce

Permissive

3、执行备份

[mysql@rh64 backup]$ sh bak.sh

Warning: Using a password on the command line interface can be insecure.

Warning: Using a password on the command line interface can be insecure.

Warning: Using a password on the command line interface can be insecure.

Warning: Using a password on the command line interface can be insecure.

[mysql@rh64 backup]$

4、验证备份

[mysql@rh64 prod]$ ls -l

total 356

-rwxrwxrwx. 1 mysql mysql 127 Oct 15 12:20 prod-2015-10-15 12-20-48.tar.gz

-rwxrwxrwx. 1 mysql mysql 129 Oct 15 12:24 prod-2015-10-15 12-24-36.tar.gz

-rwxrwxrwx. 1 mysql mysql 1094 Oct 15 12:25 prod-2015-10-15 12-25-47.tar.gz

-rw-rw-r--. 1 mysql mysql 344064 Oct 15 12:25 t1.txt

-rw-rw-r--. 1 mysql mysql 600 Oct 15 12:25 t2.txt

-rw-rw-r--. 1 mysql mysql 0 Oct 15 12:25 t3.txt

-rw-rw-r--. 1 mysql mysql 9 Oct 15 12:25 tab.txt

[mysql@rh64 prod]$ head t1.txt

1 tom

2 jerry

3 rose

1 tom

2 jerry

3 rose

1 tom

2 jerry

3 rose

1 tom

[mysql@rh64 prod]$