在上一篇文章（MySQL备份与恢复之冷备）中，我们提到了冷备。但是有个问题，我们存储的数据文件是保存在当前本地磁盘的，如果这个磁盘挂掉，那我们存储的数据不就丢失了，这样备份数据不就功亏一篑，劳而无功。所以真实环境中我们多准备几块磁盘，然后再在这些磁盘上搭建LVM，把MySQL的数据目录挂载到LVM上，这样数据就不是存储在当前磁盘上，就可以保证数据的安全性。
示意图
真实环境使用冷备模拟
第一步，需要提前规划好磁盘，这里做模拟，添加两磁盘
第二步，对磁盘进行分区
[root@serv01 ~]# fdisk /dev/sdb [root@serv01 ~]# fdisk /dev/sdc [root@serv01 ~]# ll /dev/sd[bc]1 brw-rw----. 1 root disk 8, 17 Sep 10 18:06 /dev/sdb1 brw-rw----. 1 root disk 8, 33 Sep 10 18:09 /dev/sdc1
第三步，yum安装lvm2
[root@serv01 ~]# yum install lvm2 -y
第四步，创建物理卷
[root@serv01 ~]# pvcreate /dev/sdb1 /dev/sdc1 Physical volume "/dev/sdb1" successfully created Physical volume "/dev/sdc1" successfully created
第五步，创建卷组
[root@serv01 ~]# vgcreate data /dev/sdb1 /dev/sdc1 Volume group "data" successfully created
第六步，创建逻辑卷
[root@serv01 ~]# lvcreate -L 2G -n mydata data Logical volume "mydata" created
第七步，格式化磁盘
[root@serv01 ~]# mkfs.ext4 /dev/data/mydata mke2fs 1.41.12 (17-May-2010) Filesystem label= OS type: Linux Block size=4096 (log=2) Fragment size=4096 (log=2) Stride=0 blocks, Stripe width=0 blocks 131072 inodes, 524288 blocks 26214 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=536870912 16 block groups 32768 blocks per group, 32768 fragments per group 8192 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912 Writing inode tables: done Creating journal (16384 blocks): done Writing superblocks and filesystem accounting information: done This filesystem will be automatically checked every 28 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override.
第八步，冷备
[root@serv01 ~]# ls /usr/local/mysql/data/ crm ib_logfile0 mysql-bin.000001 mysql-bin.000005 mysql-bin.000009 mysql-bin.000013 mysql-bin.index test game ib_logfile1 mysql-bin.000002 mysql-bin.000006 mysql-bin.000010 mysql-bin.000014 performance_schema hello larrydb mysql-bin.000003 mysql-bin.000007 mysql-bin.000011 mysql-bin.000015 serv01.host.com.err ibdata1 mysql mysql-bin.000004 mysql-bin.000008 mysql-bin.000012 mysql-bin.000016 serv01.host.com.pid [root@serv01 opt]# tar -cvPzf mysql01.tar.gz /usr/local/mysql/data/
第九步，删除数据库文件
[root@serv01 ~]# rm -rf /usr/local/mysql/data/*
第十步，挂载
[root@serv01 ~]# mount /dev/data/mydata /usr/local/mysql/data/ [root@serv01 ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/sda2 9.7G 2.4G 6.8G 27% / tmpfs 188M 0 188M 0% /dev/shm /dev/sda1 194M 25M 160M 14% /boot /dev/sda5 4.0G 160M 3.7G 5% /opt /dev/sr0 3.4G 3.4G 0 100% /iso /dev/mapper/data-mydata 2.0G 67M 1.9G 4% /usr/local/mysql/data
第十一步，将挂载信息写入配置文件
[root@serv01 opt]# echo "/dev/mapper/data-mydata /usr/local/mysql/data ext4 defaults 1 2" >> /etc/fstab [root@serv01 opt]# tail -n1 /etc/fstab /dev/mapper/data-mydata /usr/local/mysql/data ext4 defaults 1 2
第十二步，停掉数据库
[root@serv01 ~]# /etc/init.d/mysqld stop ERROR! MySQL server PID file could not be found! [root@serv01 ~]# ps -ef | grep mysqld root 1055 1 0 18:05 ? 00:00:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/usr/local/mysql/data --pid-file=/usr/local/mysql/data/serv01.host.com.pid mysql 1332 1055 0 18:05 ? 00:00:00 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=/usr/local/mysql/data/serv01.host.com.err --pid-file=/usr/local/mysql/data/serv01.host.com.pid --socket=/tmp/mysql.sock --port=3306 root 1885 1490 0 18:18 pts/0 00:00:00 grep mysqld [root@serv01 ~]# pkill -9 mysql [root@serv01 ~]# ps -ef | grep mysqld root 1888 1490 0 18:18 pts/0 00:00:00 grep mysqld [root@serv01 ~]# chown mysql.mysql /usr/local/mysql/data/ -R [root@serv01 opt]# ll /usr/local/mysql/data/ total 0 [root@serv01 opt]# ll /usr/local/mysql/data/ -d drwxr-xr-x. 2 mysql mysql 4096 Sep 10 18:17 /usr/local/mysql/data/
第十三步，恢复数据
[root@serv01 opt]# tar -xPvf mysql01.tar.gz
第十四步，启动数据库，登录MySQL，然后查看数据是否丢失
[root@serv01 opt]# /etc/init.d/mysqld start Starting MySQL SUCCESS! [root@serv01 ~]# mysql Welcome to the MySQL monitor. Commands end with ; or g. Your MySQL connection id is 1 Server version: 5.5.29-log Source distribution Copyright (c) 2000, 2012, 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> use larrydb; Database changed mysql> show tables; +-------------------+ | Tables_in_larrydb | +-------------------+ | class | | stu | +-------------------+ 2 rows in set (0.00 sec) mysql> select * from class; +------+--------+ | cid | cname | +------+--------+ | 1 | linux | | 2 | oracle | +------+--------+ 2 rows in set (0.01 sec) mysql> select * from stu; +------+---------+------+ | sid | sname | cid | +------+---------+------+ | 1 | larry01 | 1 | | 2 | larry02 | 2 | +------+---------+------+ 2 rows in set (0.00 sec)
第十五步，使用LVS的快照功能创建快照，快照不需要格式化。
[root@serv01 opt]# lvcreate -L 100M -s -n smydata /dev/data/mydata Logical volume "smydata" created
第十六步，挂载
[root@serv01 opt]# mount /dev/data/smydata /mnt [root@serv01 opt]# df -h Filesystem Size Used Avail Use% Mounted on /dev/sda2 9.7G 2.4G 6.8G 27% / tmpfs 188M 0 188M 0% /dev/shm /dev/sda1 194M 25M 160M 14% /boot /dev/sda5 4.0G 161M 3.7G 5% /opt /dev/sr0 3.4G 3.4G 0 100% /iso /dev/mapper/data-mydata 2.0G 98M 1.8G 6% /usr/local/mysql/data /dev/mapper/data-smydata 2.0G 98M 1.8G 6% /mnt
第十七步，模拟数据丢失和验证快照的数据不会受本身数据的影响
[root@serv01 opt]# cd /mnt [root@serv01 mnt]# ls crm ib_logfile1 mysql-bin.000003 mysql-bin.000008 mysql-bin.000013 mysql-bin.index game larrydb mysql-bin.000004 mysql-bin.000009 mysql-bin.000014 performance_schema hello mysql mysql-bin.000005 mysql-bin.000010 mysql-bin.000015 serv01.host.com.err ibdata1 mysql-bin.000001 mysql-bin.000006 mysql-bin.000011 mysql-bin.000016 serv01.host.com.pid ib_logfile0 mysql-bin.000002 mysql-bin.000007 mysql-bin.000012 mysql-bin.000017 test #进入数据目录，创建一个文件 [root@serv01 ~]# cd /usr/local/mysql/data/ [root@serv01 data]# touch aa01.txt #进入快照挂载目录，发现没有这个文件 [root@serv01 mnt]# ls aa01.txt ls: cannot access aa01.txt: No such file or directory
第十八步，备份数据
[root@serv01 mnt]# cd /databackup/ [root@serv01 databackup]# ll total 976 -rw-r--r--. 1 root root 995761 Sep 10 17:47 mysql01.tar.gz [root@serv01 databackup]# /etc/init.d/mysqld status SUCCESS! MySQL running (2198) [root@serv01 databackup]# tar -cvzf mysql02.tar.gz /mnt [root@serv01 mnt]# rm -rf /usr/local/mysql/data/* [root@serv01 mnt]# /etc/init.d/mysqld stop ERROR! MySQL server PID file could not be found! [root@serv01 mnt]# pkill -9 mysql [root@serv01 mnt]# ps -ef | grep mysqld | grep grep -v [root@serv01 mnt]# cd /usr/local/mysql/data/ [root@serv01 data]# ll total 0
第十九步，恢复数据，启动数据库，登录MySQL，然后查看数据是否丢失
[root@serv01 data]# tar -xvf /databackup/mysql02.tar.gz [root@serv01 data]# ls mnt [root@serv01 data]# cd mnt/ [root@serv01 mnt]# mv ./* ../ [root@serv01 mnt]# cd .. [root@serv01 data]# ls crm ib_logfile0 mysql mysql-bin.000004 mysql-bin.000008 mysql-bin.000012 mysql-bin.000016 serv01.host.com.err game ib_logfile1 mysql-bin.000001 mysql-bin.000005 mysql-bin.000009 mysql-bin.000013 mysql-bin.000017 serv01.host.com.pid hello larrydb mysql-bin.000002 mysql-bin.000006 mysql-bin.000010 mysql-bin.000014 mysql-bin.index test ibdata1 mnt mysql-bin.000003 mysql-bin.000007 mysql-bin.000011 mysql-bin.000015 performance_schema [root@serv01 data]# /etc/init.d/mysqld start Starting MySQL SUCCESS! [root@serv01 data]# mysql Welcome to the MySQL monitor. Commands end with ; or g. Your MySQL connection id is 1 Server version: 5.5.29-log Source distribution Copyright (c) 2000, 2012, 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> use larrydb; Database changed mysql> select * from class; +------+--------+ | cid | cname | +------+--------+ | 1 | linux | | 2 | oracle | +------+--------+ 2 rows in set (0.00 sec) mysql> select * from stu; +------+---------+------+ | sid | sname | cid | +------+---------+------+ | 1 | larry01 | 1 | | 2 | larry02 | 2 | +------+---------+------+ 2 rows in set (0.00 sec)
本文主要是在真实环境实现冷备份，保证数据的安全性，很有实用价值，有需要的朋友可以收藏起来。
