Mysql中-Xtrabackup备份和恢复应用

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maxhua 2018-06-28 01:02:58 博主文章分类：数据库 ©著作权

文章标签 全量增量 mysql备份 xtrabackup innobackupex 文章分类 MySQL 数据库

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关于Xtrabackup(又或innobackupex)的介绍，详细参考官方文档

Xtrabackup安装指南

文件准备

[root@wuxiang11 ~]# cd percona-xtrabackup/
[root@wuxiang11 percona-xtrabackup]# ls
libev-4.15-1.el6.rf.x86_64.rpm  percona-release-0.1-4.noarch.rpm  percona-xtrabackup-24-2.4.4-1.el7.x86_64.rpm

开始安装依赖文件

[root@wuxiang11 percona-xtrabackup]# rpm -ivh libev-4.15-1.el6.rf.x86_64.rpm 
warning: libev-4.15-1.el6.rf.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 6b8d79e6: NOKEY
Preparing...                ########################################### [100%]
   1:libev                  ########################################### [100%]

安装-01

[root@wuxiang11 percona-xtrabackup]# rpm -ivH percona-release-0.1-4.noarch.rpm
Preparing packages for installation...
percona-release-0.1-4

[root@wuxiang11 percona-xtrabackup]# yum list | grep percona

马上就安装完成

[root@wuxiang11 percona-xtrabackup]# yum install percona-xtrabackup-24

Loaded plugins: fastestmirror, security Setting up Install Process Loading mirror speeds from cached hostfile Resolving Dependencies --> Running transaction check ---> Package percona-xtrabackup-24.x86_64 0:2.4.11-1.el6 will be installed --> Processing Dependency: perl(DBD::mysql) for package: percona-xtrabackup-24-2.4.11-1.el6.x86_64 --> Running transaction check ---> Package perl-DBD-MySQL.x86_64 0:4.013-3.el6 will be installed --> Processing Dependency: perl(DBI::Const::GetInfoType) for package: perl-DBD-MySQL-4.013-3.el6.x86_64 --> Processing Dependency: perl(DBI) for package: perl-DBD-MySQL-4.013-3.el6.x86_64 --> Processing Dependency: libmysqlclient.so.16(libmysqlclient_16)(64bit) for package: perl-DBD-MySQL-4.013-3.el6.x86_64 --> Processing Dependency: libmysqlclient.so.16()(64bit) for package: perl-DBD-MySQL-4.013-3.el6.x86_64 --> Running transaction check ---> Package Percona-Server-shared-51.x86_64 0:5.1.73-rel14.12.625.rhel6 will be installed ---> Package perl-DBI.x86_64 0:1.609-4.el6 will be installed --> Finished Dependency Resolution

Dependencies Resolved

=============================================================================================================================================================================================== Package Arch Version Repository Size

Installing: percona-xtrabackup-24 x86_64 2.4.11-1.el6 percona-release-x86_64 8.1 M Installing for dependencies: Percona-Server-shared-51 x86_64 5.1.73-rel14.12.625.rhel6 percona-release-x86_64 2.1 M perl-DBD-MySQL x86_64 4.013-3.el6 centos6.7_64 134 k perl-DBI x86_64 1.609-4.el6 centos6.7_64 705 k

Transaction Summary

Install 4 Package(s)

Total download size: 11 M Installed size: 12 M Is this ok [y/N]: y Downloading Packages: (1/4): Percona-Server-shared-51-5.1.73-rel14.12.625.rhel6.x86_64.rpm | 2.1 MB 00:02
(2/4): percona-xtrabackup-24-2.4.11-1.el6.x86_64.rpm | 8.1 MB 00:01
(3/4): perl-DBD-MySQL-4.013-3.el6.x86_64.rpm | 134 kB 00:00
(4/4): perl-DBI-1.609-4.el6.x86_64.rpm | 705 kB 00:00

Total 2.5 MB/s | 11 MB 00:04
warning: rpmts_HdrFromFdno: Header V4 DSA/SHA1 Signature, key ID cd2efd2a: NOKEY Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-Percona Importing GPG key 0xCD2EFD2A: Userid : Percona MySQL Development Team mysql-dev@percona.com Package: percona-release-0.1-4.noarch (installed) From : /etc/pki/rpm-gpg/RPM-GPG-KEY-Percona Is this ok [y/N]: y Running rpm_check_debug Running Transaction Test Transaction Test Succeeded Running Transaction Warning: RPMDB altered outside of yum. ** Found 3 pre-existing rpmdb problem(s), 'yum check' output follows: 2:postfix-2.6.6-6.el6_5.x86_64 has missing requires of libmysqlclient.so.16()(64bit) 2:postfix-2.6.6-6.el6_5.x86_64 has missing requires of libmysqlclient.so.16(libmysqlclient_16)(64bit) 2:postfix-2.6.6-6.el6_5.x86_64 has missing requires of mysql-libs Installing : perl-DBI-1.609-4.el6.x86_64 1/4 Installing : Percona-Server-shared-51-5.1.73-rel14.12.625.rhel6.x86_64 2/4 Installing : perl-DBD-MySQL-4.013-3.el6.x86_64 3/4 Installing : percona-xtrabackup-24-2.4.11-1.el6.x86_64 4/4 Verifying : percona-xtrabackup-24-2.4.11-1.el6.x86_64 1/4 Verifying : perl-DBD-MySQL-4.013-3.el6.x86_64 2/4 Verifying : Percona-Server-shared-51-5.1.73-rel14.12.625.rhel6.x86_64 3/4 Verifying : perl-DBI-1.609-4.el6.x86_64 4/4

Installed: percona-xtrabackup-24.x86_64 0:2.4.11-1.el6

Dependency Installed: Percona-Server-shared-51.x86_64 0:5.1.73-rel14.12.625.rhel6 perl-DBD-MySQL.x86_64 0:4.013-3.el6 perl-DBI.x86_64 0:1.609-4.el6

Complete!


> 检验是否安装成功

[root@wuxiang11 percona-xtrabackup]# rpm -qa|grep xtrabackup percona-xtrabackup-24-2.4.11-1.el6.x86_64 [root@wuxiang11 percona-xtrabackup]#


# 备份思路
Xtrabackup提供了全量备份和增量备份两种方式，全量就不解释了，增量是指其可以只备份指定位置后的新增数据。本文介绍的增量备份方法使用到了LSN(Log Sequence Number)，可以从备份成功文件夹的xtrabackup_checkpoints文件中获取，其中to_lsn就是下次增量备份的起始位置。
结合两者，我们可以得到下图的备份思路。
![](http://i2.51cto.com/images/blog/201806/28/ba1350e285096853b6425f74238b7f96.jpg?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_30,g_se,x_10,y_10,shadow_20,type_ZmFuZ3poZW5naGVpdGk=)

**解释如下：**

1. 由于全量备份和增量备份的命令参数不同，所以首先要判断是否需要全量备份。
2.  如果是全量备份，那么便执行命令，备份成功后，记录xtrabackup_checkpoints文件中的to_lsn，以便后面进行增量备份
3.  如果是增量备份，那么首先读取上次备份时记录下的to_lsn，如果读取失败，报错并结束。否则执行相应命令，备份成功后记录to_lsn。


### 编写一个简单的脚本：db-backup.sh，如下所示：

#!/bin/sh

xtrabackup的相关配置

INNOBACKUPEX="innobackupex " MY_CNF="/home/config/mysql/3307.backup.cnf" MY_USER="xtrabackup" MY_PASSWORD="xtrabackup" MY_SOCKET="/home/socket/mysql/3307.sock"

远程备份机文件名配置

REMOTE_HOST="dbbackup" REMOTE_DIR="/home/backup/mysql/test" LOCAL_LSN_FILE="~/.to_lsn_important" DATE_NAME=date +%Y-%m-%d-%H-%M-%S REMOTE_FILE=$DATE_NAME.tar.gz LOCK_FILE="~/.mysql.backup.lock" LOCAL_BACKUP_DIR="/home/backup/mysql/test/$DATE_NAME"

输出帮助信息

function usage() { echo "Usage:" echo "-f db will be backuped fully with this parameter. If not , incrementally. " }

#防止同时执行两个备份命令，发生冲突 if [ -f $LOCK_FILE ] ;then echo 'Mysql backup lockfile is locked!' exit 0 fi

full=0

while getopts "fh" arg #选项后面的冒号表示该选项需要参数 do case $arg in f)
full=1 ;; h) # 输出帮助信息 usage exit 0 ;; esac done

echo "backup dir is $REMOTE_DIR/$REMOTE_FILE"

backup up db to remote host

echo "start to backup db!"date +%Y-%m-%d-%H-%M-%S if [ "$full"x = "1"x ] ;then # 全量备份 echo '1' > $LOCK_FILE $INNOBACKUPEX --defaults-file=$MY_CNF --user=$MY_USER --password=$MY_PASSWORD --socket=$MY_SOCKET ./ --stream=tar | gzip | ssh $REMOTE_HOST "cat - > $REMOTE_DIR/FULL-$REMOTE_FILE" ssh $REMOTE_HOST "cd $REMOTE_DIR;rm -f xtrabackup_checkpoints;tar zxfi $REMOTE_DIR/FULL-$REMOTE_FILE xtrabackup_checkpoints " toLSN=$( ssh $REMOTE_HOST "cat $REMOTE_DIR/xtrabackup_checkpoints|grep to_lsn|awk -F= '{gsub(/ /,"",$2);print $2}'" ) if [ $toLSN ] ;then echo $toLSN > $LOCAL_LSN_FILE else echo 'no lsn from remote host!please check!' fi else # 增量备份 if [ -f $LOCAL_LSN_FILE ] ;then toLSN=cat $LOCAL_LSN_FILE fi

if [ ! $toLSN ] ;then
    echo 'last LSN is not set !please check!'
    exit 0
fi

echo '1' > $LOCK_FILE
mkdir -p $LOCAL_BACKUP_DIR
echo "last to lsn is "$toLSN
$INNOBACKUPEX --parallel=6 --defaults-file=$MY_CNF --user=$MY_USER --password=$MY_PASSWORD --socket=$MY_SOCKET --incremental --incremental-lsn=$toLSN $LOCAL_BACKUP_DIR 2>/tmp/innobackexLog
toLSN=$( cd $LOCAL_BACKUP_DIR/*; cat xtrabackup_checkpoints|grep to_lsn|awk -F= '{gsub(/ /,"",$2);print $2}' )
echo "new to lsn is "$toLSN;
if [ $toLSN ] ;then
    echo $toLSN > $LOCAL_LSN_FILE
    cd $LOCAL_BACKUP_DIR/*;tar zc .|ssh $REMOTE_HOST "cat - > $REMOTE_DIR/$REMOTE_FILE"
    echo "save file to $REMOTE_HOST @ $REMOTE_DIR/$REMOTE_FILE"
else
    echo 'no lsn from local backup file!delete remote backup file!'$LOCAL_BACKUP_DIR/$REMOTE_FILE
fi
echo "remove $LOCAL_BACKUP_DIR"
rm -rf $LOCAL_BACKUP_DIR

rm -f $LOCK_FILE echo "end to backup db!"date +%Y-%m-%d-%H-%M-%S

将上述脚本配置好后，放到mysql主机上，执行 sh db-backup.sh -f进行全量备份，之后将sh backup.sh添加到crontab中每小时增量备份一次就可以了。




**注意--parallel=6使用是有条件的，[参考文档](https://www.percona.com/doc/percona-xtrabackup/2.1/innobackupex/parallel_copy_ibk.html)**




### 恢复思路

一旦线上数据库发生宕机之类的灾难性事故，备份数据就要立马发挥作用了。打开备份文件夹一看，如上面的图，每小时一个压缩文件，时间久了，茫茫多，上百个压缩文件，简直是一定的，这必须得来个脚本自动化恢复数据才成。思路很简单，见下图：

![](http://i2.51cto.com/images/blog/201806/28/f0104f3e459944509e85c6ca01412edb.jpg?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_30,g_se,x_10,y_10,shadow_20,type_ZmFuZ3poZW5naGVpdGk=)


**** 解释如下：**** 

1. 先解压，没啥说的。
2. 找到全量备份的数据，因为增量备份也是以此为基准进行的。上面备份的时候，全量备份文件命名以FULL开头便是为了此处便于查找。
3. 先恢复全量备份数据，然后按照时间顺序恢复增量备份的数据。
4. 将数据恢复到mysql中
5. 启动mysql，连上看看有没问题。

### 简单的实现脚本，我们叫它restore.sh，如下所示

#!/bin/sh BACK_DIR="/home/backup/mysql/test" RESTORE_DIR="/home/tmpback/test"

xtrabackup恢复时使用的配置文件可能与数据库配置文件不同

RESTORE_MY_CNF="/home/config/mysql/3307.backup.cnf"

启动mysql需要的配置文件，按需设定

MY_CNF="/home/config/mysql/3307.cnf" MY_DATA_DIR="/home/data/mysql/3307" MY_SOCK_DIR="/home/socket/mysql/" MY_LOG_DIR="/home/logs/mysqld/3307"

#extract all tar file fullFileName="" for file in $( ls $BACK_DIR | grep "tar.gz" ) do fileName=${file%.tar.gz} full=${file%%-*} if [ "${full}"x = "FULL"x ] ;then fullFileName=$fileName fi DEST_DIR="$RESTORE_DIR/$fileName" if [ -d $DEST_DIR ] ;then echo "$DEST_DIR exists!" else mkdir -p $DEST_DIR echo "start to extract file $file to $DEST_DIR" tar zxif $BACK_DIR/$file -C $RESTORE_DIR/$fileName echo "end to extract file "$file fi done

echo "full backup dir is "$fullFileName

echo "**start to repare full backup dir"

恢复全量数据

echo "innobackupex --apply-log --redo-only --use-memory=4G $RESTORE_DIR/$fullFileName" innobackupex --apply-log --redo-only --use-memory=4G "$RESTORE_DIR/$fullFileName"

echo "**end to repare full backup dir"

恢复增量数据

for file in $( ls $RESTORE_DIR|grep -v "FULL" ) do echo "**start to repare $file" echo "innobackupex --apply-log --redo-only --use-memory=4G $RESTORE_DIR/$fullFileName --incremental-dir=$RESTORE_DIR/$file" innobackupex --apply-log --redo-only --use-memory=4G "$RESTORE_DIR/$fullFileName" --incremental-dir="$RESTORE_DIR/$file"

echo "**end to repare $file"

done

echo "**start to copy back data to mysql" rm -rf $MY_DATA_DIR mkdir $MY_DATA_DIR mkdir $MY_SOCK_DIR mkdir $MY_LOG_DIR

#将数据恢复到mysql中 echo "innobackupex --defaults-file=$RESTORE_MY_CNF --copy-back $RESTORE_DIR/$fullFileName" innobackupex --defaults-file=$RESTORE_MY_CNF --copy-back $RESTORE_DIR/$fullFileName echo "**end to copy back data to mysql"

chown -R mysql:mysql $MY_DATA_DIR chown -R mysql:mysql $MY_SOCK_DIR chown -R mysql:mysql $MY_LOG_DIR

echo "All data has been restored! Try to start mysql now"

echo "mysqld_multi --defaults-file=$MY_CNF start 1"


使用方法很简单，配置好后，直接运行sh restore.sh就可以了。

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