linux实验（数据库备份）

以下所有操作皆以机房电脑上的虚拟机为基础环境

下载链接：Linux课程机房虚拟机#

切换到root用户
```
su - root
```

安装数据库mysql 5.7

rpm -ivh https://mirrors4.tuna.tsinghua.edu.cn/mysql/yum/mysql-5.7-community-el7-x86_64/mysql-community-common-5.7.29-1.el7.x86_64.rpm https://mirrors4.tuna.tsinghua.edu.cn/mysql/yum/mysql-5.7-community-el7-x86_64/mysql-community-libs-5.7.29-1.el7.x86_64.rpm https://mirrors4.tuna.tsinghua.edu.cn/mysql/yum/mysql-5.7-community-el7-x86_64/mysql-community-client-5.7.29-1.el7.x86_64.rpm https://mirrors4.tuna.tsinghua.edu.cn/mysql/yum/mysql-5.7-community-el7-x86_64/mysql-community-server-5.7.29-1.el7.x86_64.rpm --force --nodeps

配置数据库cnf文件

vim /etc/my.cnf

在文件中添加以下代码：

kip-grant-tables
character_set_server=utf8
init_connect='SET NAMES utf8'

在这里插入图片描述

启动数据库
```
systemctl start mysqld.service
```

进入数据库并配置密码

mysql
update mysql.user set authentication_string=password('123456') where user='root';

使配置生效
```
flush privileges;
```
退出数据库
```
exit
```
停止数据库
```
systemctl stop  mysqld.service
```
编辑my.cnf配置文件将：skip-grant-tables这一行注释掉
```
vim /etc/my.cnf
```
重启数据库
```
systemctl start mysqld.service
```
再次登录数据库
```
mysql -uroot -p123456
```

创建数据库和表

CREATE DATABASE IF NOT EXISTS Student;
USE Student;
CREATE TABLE `user` (
  `id` INT NOT NULL AUTO_INCREMENT,
  `name` VARCHAR(255) NULL,
  `sex` VARCHAR(255) NULL,
  `phone` VARCHAR(255) NULL,
  PRIMARY KEY (`id`)
);
INSERT INTO `user` VALUES (1, 'zhangsan', '1', '123456');
INSERT INTO `user` VALUES (2, 'lisi', '1', '123456');
INSERT INTO `user` VALUES (3, 'wangwu', '1', '123467989');
INSERT INTO `user` VALUES (4, 'chuanchuan', '2', '123456789');

退出数据库
```
exit
```

创建数据库备份脚本

vi cmysql.sh

粘贴以下内容

#!/bin/bash
# 要备份的数据库列表
DBLIST="mysql Student"

# 要备份的目录
BACKUPDIR=/mydata/backups/data/mysql

# 要保存的时间
NUMDAYS=30

# 备份要用到Linux命令和MySQL数据库配置
FINDCMD="find"
MYSQLCMD="mysql"
MyUSER="root"		# USERNAME
MyPASS="123456"			# PASSWORD
MyHOST="localhost"	# Hostname
DUMPCMD="mysqldump -u$MyUSER -h $MyHOST -p$MyPASS --lock-tables --databases"
GZIPCMD="gzip"

# 备份的日期
BACKUPDATE=`date +%Y%m%d_%H%M`

function USAGE() {
cat << EOF

usage: $0 options

This script backs up a list of MySQL databases.

OPTIONS:
 -h Show this message
 -a Backup all databases
 -l Databases to backup (space seperated)
 -n Number of days to keep backups
EOF
}

while getopts "hal:n:" opt;
do
  case $opt in
    a)
      DBLIST=""
      ;;
    h)
      USAGE
	  exit1
	  ;;
	l)
	  DBLIST="$OPTARG"
	  ;;
	n)
	  NUMDAYS="$OPTARG"
	  ;;
	\?)
	  USAGE
	  exit
	  ;;
	:)
	  echo "Option -$OPTARG requires an argument.">&2
	  exit 1
	  ;;
	esac
done

function ERROR() {
  echo && echo "[error] $@"
  exit 1
}

function NOTICE() {
  echo && echo "[notice] $@"
}

function RUNCMD() {
  echo $@
  eval $@
}

# 用备份的数据作健壮性判断
if [ ! -n "$DBLIST" ]; then
  DBLIST= `$MYSQLCMD -N -s -e "show databases" | grep -viE ' (information_schema | performance_schema|mysql|test)'`

  if [ ! -n "$DBLIST" ]; then
    ERROR "Invalid database list"
  fi
fi

if [ ! -n "$BACKUPDIR" ]; then
  ERROR "Invalid backup directory"
fi

if [[ ! $NUMDAYS =~ ^[0-9]+$ ]]; then
  ERROR "Invalid number of days: $NUMDAYS"
elif [ "$NUMDAYS" -eq "0" ]; then
  ERROR "Number of days must be greater than zero"
fi

# 屏蔽字
umask 077

# $BACKUPDIR是前面定义的备份的目录变量
RUNCMD mkdir -p -v $BACKUPDIR

if [ ! -d $BACKUPDIR ]; then
  ERROR "Invalid directory: $BACKUPDIR"
fi

NOTICE "Dumping MySQL databases..."
RC=0

for database in $DBLIST; do
  NOTICE "Dumping $database..."
  RUNCMD "$DUMPCMD $database | $GZIPCMD > $BACKUPDIR/${database}_$BACKUPDATE.sql.gz"

  RC=$?
  if [ $RC -gt 0 ]; then
    continue;
  fi
done

if [ $RC -gt 0 ]; then
  ERROR "MySQLDump failed!"
else
  NOTICE "Removing dumps older than $NUMDAYS days..."
  RUNCMD "$FINDCMD $BACKUPDIR -name \" *.sql.gz\" -type f -mtime +$NUMDAYS -print0 | xargs -0 rm -fv"

  NOTICE "Listing backup directory contents..."
  RUNCMD ls -la $BACKUPDIR

  NOTICE "MySQLDump is complete!"
fi

# exit 0