关于Xtrabackup(又或innobackupex)的介绍，详细参考官方文档https://www.percona.com/doc/percona-xtrabackup/2.1/index.html
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 <[email protected]>
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。
解释如下：
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。
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
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
fi
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：
解释如下：
- 先解压，没啥说的。
- 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。
- 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。
- 将数据恢复到mysql中
- 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。