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快照和复制技术的联合能够保障咱们失去一个实时的在线 MySQL 备份解决方案 当主库产生误操作时，只须要复原备库上的快照，而后再依据 binlog 执行 point-in-time 的复原即可 上面假设一个场景：主从架构，没有提早，某 DBA 误操作：drop database 接下来咱们依照以上场景进行备份复原模仿测试.
1. 主库筹备测试数据
mysql> create database cnfol;
Query OK, 1 row affected (0.00 sec)
mysql> create table cnfol.t (id int primary key);
Query OK, 0 rows affected (0.02 sec)
mysql> insert into cnfol.t select 1;
Query OK, 1 row affected (0.01 sec)
Records: 1 Duplicates: 0 Warnings: 0
mysql> insert into cnfol.t select 2;
Query OK, 1 row affected (0.00 sec)
Records: 1 Duplicates: 0 Warnings: 0到备库确认：
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| cnfol |
| mysql |
| test |
+--------------------+
4 rows in set (0.00 sec)
mysql> select * from cnfol.t;
+----+
| id |
+----+
| 1 |
| 2 |
+----+
2 rows in set (0.00 sec)2. 加个全局读锁 在备库
mysql> flush tables with read lock;
Query OK, 0 rows affected (0.00 sec)3. 为备库所在分区创立快照
[root@localhost ~]# lvcreate --size 1G --snapshot --name backup_mysql /dev/vg/mysql
Logical volume "backup_mysql" created
[root@localhost ~]# lvs
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
backup_mysql vg swi-a- 1.00G mysql 0.00
mysql vg owi-ao 2.00G 4. 获取二进制日志坐标
在备库：mysql> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000003 | 727 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)解锁 在备库：
mysql> unlock tables;
Query OK, 0 rows affected (0.00 sec)6. 挂载快照
[root@localhost ~]# mount /dev/vg/backup_mysql /mnt/backup
[root@localhost ~]# cd /mnt/backup/mysql/data/cnfol/ && ls -alh
总计 32K
drwx------ 2 mysql dba 4.0K 10-14 09:57 .
drwx------ 5 mysql dba 4.0K 10-14 09:57 ..
-rw-rw---- 1 mysql dba 61 10-14 09:57 db.opt
-rw-rw---- 1 mysql dba 8.4K 10-14 09:57 t.frm
-rw-rw---- 1 mysql dba 14 10-14 09:57 t.MYD
-rw-rw---- 1 mysql dba 2.0K 10-14 10:06 t.MYI7. 主库某无教训 DBA 误操作
mysql> drop database cnfol;
Query OK, 1 row affected (0.05 sec)记录下此时工夫：2013-10-14 10:17:10
备库确认是否存在库 cnfol:
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| test |
+--------------------+
3 rows in set (0.01 sec)8. 备份快照
[root@localhost backup]# pwd
/mnt/backup
[root@localhost backup]# tar -jcv -f /mnt/snapshot/mysql.tar.bz2 *这里做备份的起因有 2 点 其一，低廉的 IO，因为磁头要在快照区和零碎区来回跑 其二，快照区空间有余，因为是 COW 原理
9. 删除快照
[root@localhost ~]# umount /mnt/backup
[root@localhost ~]# lvremove --force /dev/vg/backup_mysql
Logical volume "backup_mysql" successfully removed10. 格式化备库所在分区
[mysql@localhost ~]$ mysqladmin -uroot -poracle shutdown
131014 10:32:40 mysqld_safe mysqld from pid file /mnt/lvm/mysql/data/localhost.localdomain.pid ended
[1]+ Done mysqld_safe
[root@localhost ~]# umount /mnt/lvm
[root@localhost ~]# mkfs -t ext3 /dev/vg/mysql
[root@localhost ~]# mount /dev/vg/mysql /mnt/lvm
[root@localhost ~]# lvs
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
mysql vg -wi-ao 2.00G
[root@localhost ~]# vgs
VG #PV #LV #SN Attr VSize VFree
vg 4 1 0 wz--n- 3.81G 1.81G11. 解压缩快照到备库所在分区
# tar -jxv -f /mnt/snapshot/mysql.tar.bz2 -C /mnt/lvm/
[root@localhost lvm]# pwd
/mnt/lvm
[root@localhost lvm]# ls
lost+found mysql12. 启动 MySQL
13. 利用 binlog 执行 point-in-time 复原
[mysql@localhost ~]$ mysqlbinlog --stop-datetime="2013-10-14 10:17:10" /mnt/lvm/mysql/data/mysql-bin.000003 | mysql -uroot -poracle14. 确认数据
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| cnfol |
| mysql |
| test |
+--------------------+
4 rows in set (0.00 sec)
mysql> select * from cnfol.t;
+----+
| id |
+----+
| 1 |
| 2 |
+----+
2 rows in set (0.00 sec)福利：豆花同学为大家精心整顿了一份对于 linux 和 python 的学习材料大合集！有须要的小伙伴们，关注豆花集体公众号：python 头条！回复关键词“材料合集”即可收费支付！
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