linux下利用shell脚本和mysqldump热备份和恢复mysql

对mifeng数据库进行每周六3：33完全热备份，并可以完全恢复！

一、先建立备份脚本

#vi /mifengbackup/backup.sh

#!bin/bash
cd /mifengbackup
echo "You are in backup dir"
mv backup* /oldbackup
echo "Old dbs are moved to oldbackup folder"
File = backup-$Now.sql
mysqldump -uroot -p123456 --quick --databases database-names --flush-logs --single-transaction > $File
echo "Your database backup successfully completed"

上面脚本文件保存为backup.sh，并且系统中已经创建两个目录/oldbackup和/mifengbackup。每次执行backup.sh时都会先将/mifengbackup目录下所有名称为backup开头的文件移到/oldbackup目录。

对于具体备份sql如果不熟悉，可以看我的这篇文章：mysqldump使用大全

二、为上述脚本制定执行计划

#crontab -e
30 1 * * * /backup.sh

更多关于crontab知识，参阅：Linux定时任务Crontab命令详解

附mysqldump参数说明：MYSQLDUMP参数详解（转）写得很详细！

到了计划任务执行的时间，执行好后会给我们发一封邮件，这是给我们的提示

You have new mail in /var/spool/mail/root

根据提示查看这封邮件

[root@localhost mail]# vi root
X-Original-To: root
Delivered-To: root@localhost.localdomain
Received: by localhost.localdomain (Postfix, from userid 0)
        id 46BD24493CA2; Sat, 22 Dec 2018 03:33:02 -0800 (PST)
From: "(Cron Daemon)" <root@localhost.localdomain>
To: root@localhost.localdomain
Subject: Cron <root@localhost> /backup.sh
Content-Type: text/plain; charset=UTF-8
Auto-Submitted: auto-generated
Precedence: bulk
X-Cron-Env: <XDG_SESSION_ID=63>
X-Cron-Env: <XDG_RUNTIME_DIR=/run/user/0>
X-Cron-Env: <LANG=en_US.UTF-8>
X-Cron-Env: <SHELL=/bin/sh>
X-Cron-Env: <HOME=/root>
X-Cron-Env: <PATH=/usr/bin:/bin>
X-Cron-Env: <LOGNAME=root>
X-Cron-Env: <USER=root>
Message-Id: <20181222113302.46BD24493CA2@localhost.localdomain>
Date: Sat, 22 Dec 2018 03:33:02 -0800 (PST)

/bin/sh: /backup.sh: No such file or directory

主要是最后一句，是错误原因，提示文件路径找不到，因为我们没有配置环境变量，所以涉及到路径的最好写绝对路径。

#vi /usr/local/mifengbackup/backup.sh

#!bin/bash
cd /usr/local/mifengbackup
echo "You are in mifengbackup dir"
mv backup* /usr/local/oldbackup
echo "Old dbs are moved to oldbackup folder"
File = backup-$Now.sql
mysqldump -h177.77.177.177 -uroot -p123456 --quick --databases mifeng --flush-logs --single-transaction > $File
echo "Your database backup successfully completed"

三、恢复备份sql文件

cd /mysqlback
tar zxvf extmail20170515.tar.gz
mv extmail20170515.sql extmail.sql
mysql -uroot -p < extmail.sql