Linux命令：MySQL系列之十四--MySQL备份与还原（LVM逻辑卷快照备份重要章节）

2022-05-08 04:42:00

通过LVM逻辑卷实现MySQL备份及还原（几乎热备）：

前提：

1、数据文件要在逻辑卷上；

2、此逻辑卷所在卷组必须有足够的空间使用快照卷；

3、数据文件和事务日志要在同一个逻辑卷上；

步骤：

1、打开会话，施加读锁，锁定所有表；

mysql> FLUSH TABLES WITH READ LOCK; #刷新表并对表施加读锁

mysql> FLUSH LOGS; #滚动日志

2、通过另一个终端，保存二进制日志文件及相关位置信息；

[root@lamp ~]# mysql -uroot -p -e 'SHOW MASTER STATUS\G' > /path/to/master.info

#不登录mysql客户端直接查看位置状态，并保存位置信息到相应目录

3、创建快照卷

[root@lamp ~]# lvcreate -L SIZE -s -p r -n LV_NAME /path/to/source_lv

#创建快照卷，-s:指定为所创建的是快照卷s=snapshot快照; -p:指定权限p=permission许可；

r:读权限;-n:指定快照名称；LV_NAME:快照名称;/path/to/source_lv:针对哪个逻辑卷目录

路径做快照;-L:指定快照卷大小。

4、释放锁

mysql> UNLOCK TABLES; #释放锁

5、挂载快照卷，并备份；

mount /dev/myvg/mydata-snap /mnt -o ro #挂载快照卷至/mnt目录，只读挂载

cp -a ./* /backup/full-backup-2017-06-06/ #挂载后把数据复制到备份目录， -a:表示

复制文件的所有属性及内容，保留源文件的所有属性及权限

6、删除快照卷

umount /mnt #备份完后卸载快照卷挂载的目录

lvremove --force /dev/myvg/mydata-snap #强制移除快照卷

rm -rf mysql-bin.* #把备份目录中的日志文件删除掉，节省空间

7、增量备份二进制日志

mysqlbinlog --start-datetime='2017-06-06 10:11:02' mysql-bin.000005 mysql-bin.000006 > /backup/incremental-`date +%F-%H-%M-%S`.sql #备份二进制日志，如果增量备份的二进制日志

含有2个或以上的日志文件，需要通过指定开始时间点来备份。

实例：通过实际操作，实现lvm逻辑卷快照备份及恢复mysql操作；

首先打开mysql客户端：

[root@lamp ~]# mysql #打开mysql客户端

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

Your MySQL connection id is 11

Server version: 5.5.28-log Source distribution

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> FLUSH TABLES WITH READ LOCK; #首先刷新表并施加读锁

Query OK, 0 rows affected (0.00 sec)

mysql> FLUSH LOGS; #滚动日志

Query OK, 0 rows affected (0.06 sec)

mysql> SHOW MASTER STATUS; #查看二进制日志位置状态

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

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

| mysql-bin.000005 | 107 | | |

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

1 row in set (0.00 sec)

不要退出或关闭此mysql客户端，重新打开一个服务器终端，执行位置信息的保存；

[root@lamp ~]# mkdir /backup #新建一个备份目录

[root@lamp ~]# mysql -e 'SHOW MASTER STATUS\G;' > /backup/master-`date +%F`.info #不登录mysql客户端，直接通过mysql -e直接编辑数据库，把查看二进制日志位置状态保存至备份目录下

[root@lamp ~]# ls /backup/

master-2017-06-06.info

对mysql数据目录执行快照（所以说通过逻辑卷备份数据库，前提必须是数据文件存放在逻辑卷上）

[root@lamp ~]# lvcreate -L 50M -s -p r -n mydata-snap /dev/myvg/mydata #对/dev/myvg/mydata逻辑卷做快照，大小为50M，-s:表示snapshot快照，-p:指定权限permission

r:读的权限read,-n:指定快照卷的名称。

Rounding up size to full physical extent 52.00 MiB

Logical volume "mydata-snap" created

[root@lamp ~]# lvs #查看逻辑卷，刚新建的快照逻辑卷

LV VG Attr LSize Origin Snap% Move Log Copy% Convert

mydata myvg owi-ao 10.00g

mydata-snap myvg sri-a- 52.00m mydata 0.02

[root@lamp ~]# mount #查看挂载相关信息

/dev/sda7 on / type ext4 (rw)

proc on /proc type proc (rw)

sysfs on /sys type sysfs (rw)

devpts on /dev/pts type devpts (rw,gid=5,mode=620)

tmpfs on /dev/shm type tmpfs (rw,rootcontext="system_u:object_r:tmpfs_t:s0")

/dev/sda1 on /boot type ext4 (rw)

/dev/sda3 on /home type ext4 (rw)

/dev/sda5 on /tmp type ext4 (rw)

/dev/sda2 on /usr/local type ext4 (rw)

/dev/mapper/myvg-mydata on /mydata type ext4 (rw)

none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)

sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)

执行完快照后，即可解锁表；

mysql> UNLOCK TABLES; #解锁

Query OK, 0 rows affected (0.00 sec)

对快照进行挂载并备份；

[root@lamp ~]# mount /dev/myvg/mydata-snap /mnt -o ro #以只读方式挂载刚做的快照卷

[root@lamp ~]# cd /mnt #进入挂载目录

[root@lamp mnt]# ls

data lost+found

[root@lamp mnt]# cd data/

[root@lamp data]# ls

hellodb ib_logfile1 lamp.pid mysql-bin.000001 mysql-bin.000004 performance_schema testdb ibdata1 jiaowu mydb mysql-bin.000002 mysql-bin.000005 stu

ib_logfile0 lamp.err mysql mysql-bin.000003 mysql-bin.index test

[root@lamp data]# mkdir /backup/full-backup-`date +%F` #创建备份目录并以时间格式命名

[root@lamp data]# cp -a ./* /backup/full-backup-2017-06-06/ #-a:复制当前目录的所有内容及其权限属性到备份的目录

[root@lamp data]# cd

[root@lamp ~]# umount /mnt #卸载挂载的目录/mnt

[root@lamp ~]# lvremove --force /dev/myvg/mydata-snap #移除刚才创建的快照卷--force强制性

Logical volume "mydata-snap" successfully removed

[root@lamp ~]# cd /backup/full-backup-2017-06-06/

[root@lamp full-backup-2017-06-06]# ls

hellodb ib_logfile1 lamp.pid mysql-bin.000001 mysql-bin.000004 performance_schema testdb ibdata1 jiaowu mydb mysql-bin.000002 mysql-bin.000005 stu

ib_logfile0 lamp.err mysql mysql-bin.000003 mysql-bin.index test

[root@lamp full-backup-2017-06-06]# rm -rf mysql-bin.* #删除相关的二进制日志文件以便节省空间

[root@lamp full-backup-2017-06-06]# ls

hellodb ib_logfile0 jiaowu lamp.pid mysql stu testdb

ibdata1 ib_logfile1 lamp.err mydb performance_schema test

root@lamp ~]# cd /mydata/data

[root@lamp data]# ls

hellodb ib_logfile1 lamp.pid mysql-bin.000001 mysql-bin.000004 performance_schema testdb ibdata1 jiaowu mydb mysql-bin.000002 mysql-bin.000005 stu

ib_logfile0 lamp.err mysql mysql-bin.000003 mysql-bin.index test

[root@lamp data]# cat /backup/master-2017-06-06.info

*************************** 1. row ***************************

File: mysql-bin.000005 #记录的二进制日志文件

Position: 107 #二进制日志的位置

Binlog_Do_DB:

Binlog_Ignore_DB:

mysql> FLUSH LOGS; #滚动日志

Query OK, 0 rows affected (0.01 sec)

mysql> USE jiaowu

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> INSERT INTO tutors(Tname) VALUES ('stu0003'); #往表tutors中插入数据,字段Tname 值stu0003

Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO tutors(Tname) VALUES ('stu0004'); #往表tutors中插入数据,字段Tname 值stu0004

Query OK, 1 row affected (0.00 sec)

mysql> SHOW MASTER STATUS; #查看此时二进制日志的位置状态信息

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

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

| mysql-bin.000006 | 575 | | |

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

1 row in set (0.00 sec)

mysql> \q

Bye

[root@lamp data]# mysqlbinlog --start-datetime='2017-06-06 10:11:02' mysql-bin.000005 mysql-bin.000006 > /backup/incremental-`date +%F-%H-%M-%S`.sql #导出二进制日志文件bin.000005和bin.000006时间点从2017-06-06 10:11:02开始后的内容

[root@lamp data]# ls /backup/incremental-2017-06-06-17-01-41.sql

/backup/incremental-2017-06-06-17-01-41.sql

[root@lamp data]# service mysqld stop #停止mysqld进程

Shutting down MySQL.. [ OK ]

[root@lamp data]# rm -rf ./* #模拟mysql数据库数据目录内容丢失（手动删除）

[root@lamp data]# ls #目录中的内容全部删除，查看显示为空

[root@lamp data]# cp -a /backup/full-backup-2017-06-06/* ./ #复制之前快照卷备份的内容至当前数据目录，-a:复制文件的内容及权限属性。

[root@lamp data]# ll #确保所有文件的属主为mysql用户

total 28712

drwx------. 2 mysql mysql 4096 Jun 2 15:30 hellodb

-rw-rw----. 1 mysql mysql 18874368 Jun 5 14:00 ibdata1

-rw-rw----. 1 mysql mysql 5242880 Jun 5 14:00 ib_logfile0

-rw-rw----. 1 mysql mysql 5242880 Jun 2 15:28 ib_logfile1

drwx------. 2 mysql mysql 4096 Jun 5 14:00 jiaowu

-rw-rw----. 1 mysql root 1853 Jun 2 15:28 lamp.err

-rw-rw----. 1 mysql mysql 6 Jun 2 15:28 lamp.pid

drwx------. 2 mysql mysql 4096 Jun 2 15:30 mydb

drwx------. 2 mysql root 4096 Jun 2 15:30 mysql

drwx------. 2 mysql mysql 4096 Jun 2 15:28 performance_schema

drwx------. 2 mysql mysql 4096 Jun 2 15:30 stu

drwx------. 2 mysql root 4096 Jun 2 15:28 test

drwx------. 2 mysql mysql 4096 Jun 2 15:30 testdb

[root@lamp data]# service mysqld start #开启mysqld进程

Starting MySQL [ OK ]

[root@lamp data]# mysql -uroot -p #登录mysql客户端

Enter password:

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

Your MySQL connection id is 3

Server version: 5.5.28-log Source distribution

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> USE jiaowu

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> SELECT * FROM tutors; #查询tutors表的内容（此时后插入的2行数据没有）

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

| TID | Tname | Gender | Age |

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

| 1 | HongQigong | M | 93 |

| 2 | HuangYaoshi | M | 63 |

| 3 | Miejueshitai | F | 72 |

| 4 | OuYangfeng | M | 76 |

| 5 | YiDeng | M | 90 |

| 6 | YuCanghai | M | 56 |

| 7 | Jinlunfawang | M | 67 |

| 8 | HuYidao | M | 42 |

| 9 | NingZhongze | F | 49 |

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

9 rows in set (0.00 sec)

mysql> SET sql_log_bin=0; #导入二进制日志前，先关闭日志记录功能0为关闭，1为打开

Query OK, 0 rows affected (0.00 sec)

mysql> SOURCE /backup/incremental-2017-06-06-17-01-41.sql #导入备份的二进制日志数据

Query OK, 0 rows affected (0.00 sec)

mysql> SELECT * FROM tutors; #再次查询tutors表的内容，此时后插入的2行数据已经生成

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

| TID | Tname | Gender | Age |

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

| 1 | HongQigong | M | 93 |

| 2 | HuangYaoshi | M | 63 |

| 3 | Miejueshitai | F | 72 |

| 4 | OuYangfeng | M | 76 |

| 5 | YiDeng | M | 90 |

| 6 | YuCanghai | M | 56 |

| 7 | Jinlunfawang | M | 67 |

| 8 | HuYidao | M | 42 |

| 9 | NingZhongze | F | 49 |

| 10 | stu0003 | M | NULL |

| 11 | stu0004 | M | NULL |

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

11 rows in set (0.00 sec)

mysql> SET sql_log_bin=1; #二进制日志导入后再打开二进制日志记录功能

Query OK, 0 rows affected (0.00 sec)

mysql> SHOW MASTER STATUS; #查看此时的二进制日志位置状态信息

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

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

| mysql-bin.000001 | 107 | | |

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

1 row in set (0.00 sec)

至此通过lvm逻辑卷和二进制cp功能实现了mysql数据库备份和还原。

本文转自wang650108151CTO博客，原文链接：，如需转载请自行联系原作者

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