Xtrabackup 数据备份工具使用方法

1.安装

1.1 简介

XtraBackup(PXB) 工具是 Percona 公司用 perl 语言开发的一个用于 MySQL 数据库物理热备的备份工具，支持 MySQl（Oracle）、Percona Server 和 MariaDB，并且全部开源。Percona-Xtrabackup的工作原理是在启动时记住日志序列号（log sequence number == LSN），然后复制数据文件。这一过程需要耗费时间，在数据复制过程中如果文件正在更改，LSN将反映数据库在不同时间点的状态。同时，每次备份过程中PerconaXtrabackup会运行一个后台进程，监视事务日志文件，并从中复制更改。PerconaXtrabackup自数据文件开始执行以来，每次更改都需要事务日志记录。

Ubuntu

example@ubuntu:~$ wget https://repo.percona.com/apt/percona-release_latest.$(lsb_release -sc)_all.deb
example@ubuntu:~$ ls -al percona-release_latest.xenial_all.deb
-rw-rw-r-- 1 example example 8900 Mar 12 21:37 percona-release_latest.xenial_all.deb
example@ubuntu:~$ sudo dpkg -i percona-release_latest.$(lsb_release -sc)_all.deb
example@ubuntu:~$ ls /etc/apt/sources.list.d/percona-original-release.list
/etc/apt/sources.list.d/percona-original-release.list
example@ubuntu:~$ sudo apt-get update
example@ubuntu:~$ sudo apt-get install percona-xtrabackup-24

Centos

[example@mail ~]$ sudo yum install https://repo.percona.com/yum/percona-release-latest.noarch.rpm
[example@mail ~]$ ls /etc/yum.repos.d/percona-original-release.repo
/etc/yum.repos.d/percona-original-release.repo
[example@mail ~]$ sudo yum list | grep percona
percona-release.noarch                  1.0-9                          installed
...
[example@mail ~]$ sudo yum install libev percona-xtrabackup-24

2.全量备份及恢复

Xtrabackup默认数据存储目录为 /var/lib/mysql，默认读取"/etc/my.cnf、/etc/mysql/my.cnf 、/usr/etc/my.cnf 、~/.my.cnf"的数据库配置，可以通过 --variable-name=value 修改默认配置

Xtrabackup 部分参数说明
- –target-dir=name 备份文件存放路径
- –backup 数据备份
- –prepare 为数据恢复做准备
- –apply-log-only 适用于增量备份恢复准备过程，不进行LSN回滚
- –use-memory 数据备份是使用的内存
- –incremental-lsn=name (–backup)仅复制比指定LSN数值高的.ibd页
- –incremental-basedir=name (–backup)新建增量备份的上次备份目录
- –incremental-dir=name (–prepare) 恢复准备阶段增量备份目录
- –databases=name --tables=name 指定数据库或表名
- –copy-back 保留备份数据并恢复数据
- –move-back 不保留备份数据并恢复数据
- –galera-info --slave-info 用于集群
- -u, --user=name -H, --host=name -P, —port=# -p, --password=name 数据库参数
数据备份

指定数据目录为/var/lib/lims_mysql，备份数据存储目录为/home/example/backup/full/

[example@mail ~]$ sudo xtrabackup -uexample -H172.17.42.1 -p --backup --datadir=/var/lib/lims_mysql/ --target-dir=/home/example/backup/full/

数据备份成功后会出现"completed OK!"提示，信息记录了 LSN为3505793

190329 14:30:28 [00] Writing /home/example/backup/full/xtrabackup_info
190329 14:30:28 [00]        ...done
xtrabackup: Transaction log of lsn (3505793) to (3505793) was copied.
190329 14:30:28 completed OK!

全量备份文件中文件列表如下：

[example@mail ~/backup/full]$ ls -al
drwxr-x--- 2 root root     4096 Mar 29 14:30 approval
-rw-r----- 1 root root      432 Mar 29 14:30 backup-my.cnf
drwxr-x--- 2 root root     4096 Mar 29 14:30 eq_stat
-rw-r----- 1 root root 79691776 Mar 29 14:30 ibdata1
drwxr-x--- 2 root root    16384 Mar 29 14:30 lims2_ali_test
drwxr-x--- 2 root root     4096 Mar 29 14:30 mysql
drwxr-x--- 2 root root     4096 Mar 29 14:30 performance_schema
drwxr-x--- 2 root root     4096 Mar 29 14:30 sj_tri
drwxr-x--- 2 root root     4096 Mar 29 14:30 unpc
-rw-r----- 1 root root       32 Mar 29 14:30 xtrabackup_binlog_info
-rw-r----- 1 root root      113 Mar 29 14:30 xtrabackup_checkpoints
-rw-r----- 1 root root      587 Mar 29 14:30 xtrabackup_info
-rw-r----- 1 root root     2560 Mar 29 14:30 xtrabackup_logfile

备份目录中的 xtrabackup_checkpoints 文件记录了备份类型，开始LSN及结束LSN

[example@mail ~/backup/full]$ sudo cat xtrabackup_checkpoints
backup_type = full-backuped
from_lsn = 0
to_lsn = 3505793
last_lsn = 3505793
compact = 0
recover_binlog_info = 0

数据恢复准备

因为数据在备份过程中会有新的事物被提交。不使用 --prepare 准备数据，会导致未提交的事物被回滚。xtrabackup 不允许未经过准备的数据进行恢复
```
[example@mail ~]$ sudo xtrabackup --prepare --target-dir=/home/example/backup/full/
...
InnoDB: Shutdown completed; log sequence number 3523624
190329 14:48:13 completed OK!
```

数据恢复

恢复数据时，MySQL的数据目录不能存在数据 && 数据库应处于关闭状态

[example@mail ~]$ sudo xtrabackup -uexample -H172.17.42.1 -p --copy-back --datadir=/var/lib/lims_mysql/ --target-dir=/home/example/backup/full/
...
190329 15:08:31 [01] Copying ./sj_tri/db.opt to /var/lib/lims_mysql/sj_tri/db.opt
190329 15:08:31 [01]        ...done
190329 15:08:32 completed OK!

使用 --copy-back 等同于复制操作，即备份数据仍然保存；

–move-back 恢复数据但不保存备份文件

若不使用xtrabackup命令，也可以使用 rsync -avrP 或 cp -r 命令。文件复制成功后，需修改数据目录属主属组为mysql

[example@mail ~]$ sudo rsync -avrP /home/example/backup/full/ /var/lib/lims_mysql
或者
[example@mail ~]$ sudo cp -r /home/example/backup/full/ /var/lib/lims_mysql
[example@mail ~]$ sudo chown -R mysql:mysql /var/lib/lims_mysql

启动数据库，查看数据状态

3.增量备份及恢复

数据备份

备份全量数据 ==>> /home/example/backup/full_backup/

[example@mail ~]$ sudo xtrabackup -uexample -H172.17.42.1 -p --backup --datadir=/var/lib/lims_mysql/ --target-dir=/home/example/backup/full_backup/
...
190329 15:30:35 [00] Writing /home/example/backup/full_backup/xtrabackup_info
190329 15:30:35 [00]        ...done
xtrabackup: Transaction log of lsn (0) to (3523633) was copied.
190329 15:30:35 completed OK!

增量数据备份01

[example@mail ~]$ sudo xtrabackup -uexample -H172.17.42.1 -p --backup --datadir=/var/lib/lims_mysql/ --target-dir=/home/example/backup/incre_backup/01/ --incremental-basedir=/home/example/backup/full_backup/
...
190329 15:44:34 [00]        ...done
xtrabackup: Transaction log of lsn (3523623) to (30338852) was copied.
190329 15:44:34 completed OK!```    增量备份数据02```shell
sudo xtrabackup -uexample -H172.17.42.1 -p --backup --datadir=/var/lib/lims_mysql/ --target-dir=/home/example/backup/incre_backup/02/ --incremental-basedir=/home/example/backup/incre_backup/01/
...
190329 16:04:34 [00]        ...done
xtrabackup: Transaction log of lsn (30338852) to (30347862) was copied.
190329 16:04:34 completed OK!

数据恢复准备

增量备份恢复准备时，除最后一个增量数据外，其他准备工作都需要使用 --apply-log-only

[example@mail ~]$ sudo xtrabackup --prepare --apply-log-only --target-dir=/home/example/backup/full_backup/
...
InnoDB: Shutdown completed; log sequence number 3523633
InnoDB: Number of pools: 1
190329 16:30:01 completed OK!

[example@mail ~]$ sudo xtrabackup --prepare --apply-log-only --target-dir=/home/example/backup/full_backup/  --incremental-dir=/home/example/backup/incre_backup/01/
...
190329 16:33:13 [00]        ...done
190329 16:33:13 completed OK!

[example@mail ~]$ sudo xtrabackup --prepare --target-dir=/home/example/backup/full_backup/  --incremental-dir=/home/example/backup/incre_backup/02/
...
InnoDB: Shutdown completed; log sequence number 30351912
190329 16:34:38 completed OK!

此时数据已全部整合到了/home/example/backup/full_backup/ 文件中

再次执行全量数据准备工作

[example@mail ~]$ sudo xtrabackup  --prepare --target-dir=/home/example/backup/full_backup/
...
190329 16:52:55 completed OK!

数据恢复

按照全量数据恢复步骤恢复即可

参考文档：

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官网地址-Xtrabackup

innobackupex(2.2版本已移除)