MySQL 复制+快照恢复误删除操作实验测试
下面假定2个场景:
场景1:主从架构,没有延迟,某DBA误操作:drop database 【复制+快照:在线备份】
场景2:存在不确定性或者风险性较大的操作,如升级测试,大表变更【啥事都在快照上折腾,不行大不了就将之删除】
场景2比较简单,随便在新建的一个快照上折腾,搞砸就把快照删除,再新建一个,2个字:随便玩
下面我们对场景1进行模拟
恢复方法:
① 恢复备库上的快照
② 根据binlog执行point-in-time恢复
先为备库创建快照
[root@localhost ~]# vgs
VG #PV #LV #SN Attr VSize VFree
vg 4 1 0 wz–n- 3.81G 1.81G
[root@localhost ~]# lvs
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
mysql vg -wi-ao 2.00G
[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
[root@localhost ~]# mount /dev/vg/backup_mysql /mnt/backup
[root@localhost ~]# cd /mnt/backup/
[root@localhost backup]# ls
lost+found mysql
[root@localhost backup]# tar -jcv -f /mnt/snapshot/mysql.tar.bz2 *
[root@localhost ~]# lvremove –force /dev/vg/backup_mysql
Logical volume “backup_mysql” successfully removed
这里为什么要先备份快照再还原呢?
其一,昂贵的IO,因为磁头要在快照区和系统区来回跑
其二,快照区空间不足,因为是COW原理
在 2013-10-12 9:57 某位无经验DBA错误地执行了drop database snapshots:
在备库上确认查看:
mysql> show databases;
+——————–+
| Database |
+——————–+
| information_schema |
| mysql |
| test |
+——————–+
可见库已经被删除了
同时在主库或者备库查看当前的二进制日志坐标并记录下来
[mysql@localhost mysql]$ mysqladmin -uroot -poracle shutdown
131012 09:59:36 mysqld_safe mysqld from pid file /mnt/lvm/mysql/data/localhost.localdomain.pid ended
[1]+ Done mysqld_safe
[root@localhost ~]# umount /mnt/backup
[root@localhost ~]# lvremove –force /dev/vg/backup_mysql
Logical volume “backup_mysql” successfully removed
[root@localhost ~]# umount /mnt/lvm
[root@localhost ~]# mkfs -t ext3 /dev/vg/mysql
[root@localhost ~]# mount /dev/vg/mysql /mnt/lvm
[root@localhost ~]# tar -jxv -f /mnt/snapshot/mysql.tar.bz2 -C /mnt/lvm
[mysql@localhost ~]$ mysqld_safe &
通过binlog执行point-in-time恢复
[mysql@localhost ~]$ mysqlbinlog –stop-datetime=”2013-10-12 10:9:56″ /mnt/lvm/mysql/data/mysql-bin.000008 | mysql -uroot -poracle
确认数据是否恢复:
mysql> show databases;
+——————–+
| Database |
+——————–+
| information_schema |
| mysql |
| snapshots |
| test |
+——————–+
4 rows in set (0.00 sec)
mysql> use snapshots;
Database changed
mysql> show tables;
+———————+
| Tables_in_snapshots |
+———————+
| t