MySQL备份与恢复-3

Posted 2021-01-23 夜间独行的浪子

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上一片myloder搞崩溃，为什么百度的博文都是抄袭一模一样的，哎烦！

这一片文章我们来介绍物理备份工具xtracebackup!

首先是安装可以percona官网下载安装，下载rpm包直接yum安装即可！

yum install -y perl-DBD-mysql perl-DBI perl-Time-HiRes libaio*         #安装依赖包
yum install -y percona-xtrabackup-24-2.4.4-1.el6.x86_64.rpm
[[email protected] ~]# xtrabackup -v
xtrabackup version 2.4.4 based on MySQL server 5.7.13 Linux (x86_64) (revision id: df58cf2)
#下载的时候尽量下载新版本的percoan，这样会有对MySQL5.7的支持
#写这个博文的时候，官网最新版本好像是2.4.14

XtraceBackup是由知名数据库软件服务企业Percona提供的一款热备工具，除了能够支持最为常见的MyISAM,INNODB引擎对象外，还支持XtraDB引擎。

查看percona的安装文件：

[[email protected] ~]# rpm -ql percona-xtrabackup-24-2.4.4-1.el6.x86_64
/usr/bin/innobackupex 
/usr/bin/xbcloud
/usr/bin/xbcloud_osenv
/usr/bin/xbcrypt
/usr/bin/xbstream                 #以专用的xbstream格式压缩xtrabackup输出的信息。也可以使用tar 
/usr/bin/xtrabackup               #最经常使用的就是这两个备份工具，其中xtracebackup只能备份INNODB存储引擎，而innobackupex对xtracebackup进行了封装，不仅能备份INNODB存储引擎，也能备份myisam存储引擎。
/usr/share/doc/percona-xtrabackup-24-2.4.4
/usr/share/doc/percona-xtrabackup-24-2.4.4/COPYING
/usr/share/man/man1/innobackupex.1.gz
/usr/share/man/man1/xbcrypt.1.gz
/usr/share/man/man1/xbstream.1.gz
/usr/share/man/man1/xtrabackup.1.gz

XtraceBackup备份有以下几个优点：

l 备份集高效，完整，可用。

l 备份任务执行过程中不会有阻塞任务

l 节省磁盘空间，降低网络带宽占用

l 备份集自动验证机制

l 恢复更快

xtrabackup必须在MySQL服务端执行（但是创建的备份集不一定是保存在本地），特别是通过innobackupex命令创建备份集时，由于操作需要连接数据库获取信息，因此还要指定的连接参数（用户名，密码），而且连接所使用的的用户，必须拥有正确的操作权限。

innobackupex的参数有很多，仅通过实例来讲解经常使用的，若需要某些参数可以查看官方文档！

一个完全备份

[[email protected] ~]# innobackupex --user=root --password=123456  /data/backup/          #备份很简单，/data/backup/为备份的目录
181128 18:50:47 innobackupex: Starting the backup operation

IMPORTANT: Please check that the backup run completes successfully.
           At the end of a successful backup run innobackupex
           prints "completed OK!".

181128 18:50:47  version_check Connecting to MySQL server with DSN ‘dbi:mysql:;mysql_read_default_group=xtrabackup;host=localhost‘ as ‘root‘  (using password: YES).
181128 18:50:47  version_check Connected to MySQL server
181128 18:50:47  version_check Executing a version check against the server...
181128 18:50:47  version_check Done.
181128 18:50:47 Connecting to MySQL server host: localhost, user: root, password: set, port: 0, socket: (null)
Using server version 5.7.22-log
innobackupex version 2.4.4 based on MySQL server 5.7.13 Linux (x86_64) (revision id: df58cf2)
xtrabackup: uses posix_fadvise().
xtrabackup: cd to /data/mysql
xtrabackup: open files limit requested 0, set to 1024
xtrabackup: using the following InnoDB configuration:
xtrabackup:   innodb_data_home_dir = .
xtrabackup:   innodb_data_file_path = ibdata1:12M:autoextend
xtrabackup:   innodb_log_group_home_dir = ./
xtrabackup:   innodb_log_files_in_group = 2
xtrabackup:   innodb_log_file_size = 50331648
InnoDB: Number of pools: 1
181128 18:50:47 >> log scanned up to (13741543758)
xtrabackup: Generating a list of tablespaces
InnoDB: Allocated tablespace ID 48 for mysql/servers, old maximum was 0
181128 18:50:48 [01] Copying ./ibdata1 to /data/backup/2018-11-28_18-50-47/ibdata1   #拷贝的是ibd文件，然后分别拷贝每张表的文件，然后再拷贝redo日志
181128 18:50:48 >> log scanned up to (13741543758)
181128 18:50:49 >> log scanned up to (13741543758)
181128 18:50:50 [01]        ...done
181128 18:50:50 [01] Copying ./mysql/servers.ibd to /data/backup/2018-11-28_18-50-47/mysql/servers.ibd
181128 18:50:50 [01]        ...done
181128 18:50:50 [01] Copying ./mysql/time_zone_name.ibd to /data/backup/2018-11-28_18-50-47/mysql/time_zone_name.ibd

......
MySQL binlog position: filename ‘test3-bin.000001‘, position ‘21818‘
181128 18:51:12 [00] Writing backup-my.cnf
181128 18:51:12 [00]        ...done
181128 18:51:12 [00] Writing xtrabackup_info
181128 18:51:12 [00]        ...done
xtrabackup: Transaction log of lsn (13741543749) to (13741543758) was copied.
181128 18:51:12 completed OK!         #出现completed OK表示备份完成！

因为过程比较长，没有粘贴，可以看一下备份的过程！

innobackupex会在备份目录下面创建以当前时间点命名的备份文件如下：

[[email protected] ~]# cd /data/backup/
[[email protected] backup]# ls
2018-11-28_18-50-47             #以当前时间点命名的备份文件集
[[email protected] backup]# cd 2018-11-28_18-50-47/
[[email protected] 2018-11-28_18-50-47]# ls          #看到的备份之后的文件集
backup-my.cnf  employees   hostinfo        ibdata1  mysql   performance_schema  sys   tpcc_test  xtrabackup_binlog_info  xtrabackup_info
cmdb           financesys  ib_buffer_pool  lianxi   mytest  sbtest              test  ts1.ibd    xtrabackup_checkpoints  xtrabackup_logfile
[[email protected] 2018-11-28_18-50-47]# cd employees; ls     #每个数据库中包含的表的结构文件（frm）和表数据文件（ibd）
current_dept_emp.frm  departments.frm  dept_emp.frm  dept_emp_latest_date.frm  dept_manager.ibd  employees.ibd  salaries.ibd  test2.frm  titles.frm
db.opt                departments.ibd  dept_emp.ibd  dept_manager.frm          employees.frm     salaries.frm   test1.frm     test3.frm  titles.ibd
[[email protected] employees]#

backup-my.cnf：　为当前数据库配置文件的备份！

xtrabackup_binlog_info：当前备份文件对应的二进制日志文件和position位置，做PIT恢复时使用。

[[email protected] 2018-11-28_18-50-47]# cat xtrabackup_info      #包含信息比较多
uuid = 85662dd9-f2fb-11e8-a47c-fa336351fc00                #当前数据库的UUID
name = 
tool_name = innobackupex                                   #包含备份的工具，备份的命令，备份工具的版本，MySQL的版本
tool_command = --user=root --password=... /data/backup/
tool_version = 2.4.4
ibbackup_version = 2.4.4
server_version = 5.7.22-log
start_time = 2018-11-28 18:50:47                           #备份的开始时间
end_time = 2018-11-28 18:51:12                             #备份的结束时间
lock_time = 0
binlog_pos = filename ‘test3-bin.000001‘, position ‘21818‘       #二进制日志的位置
innodb_from_lsn = 0
innodb_to_lsn = 13741543749                                      #刷新到lsn的位置
partial = N
incremental = N                                                  #增量备份
format = file
compact = N                                        
compressed = N
encrypted = N

[[email protected] 2018-11-28_18-50-47]# cat xtrabackup_checkpoints        #包含checkpoint的信息，以及备份方式
backup_type = full-backuped
from_lsn = 0
to_lsn = 13741543749
last_lsn = 13741543758
compact = 0
recover_binlog_info = 0

xtrabackup_logfile：【未知】

执行恢复

恢复分为两个步骤：

准备恢复：所谓准备恢复，就是要为恢复做准备。就是说备份集没办法直接拿来用，因为这中间可能存在未提交或未回滚的事务，数据文件不一致，所以需要一个队备份集的准备过程。

[[email protected] ~]# innobackupex --apply-log /data/backup/2018-11-28_18-50-47/　　　　　　　　＃准备阶段的命令　　　
181128 19:16:57 innobackupex: Starting the apply-log operation

IMPORTANT: Please check that the apply-log run completes successfully.
           At the end of a successful apply-log run innobackupex
           prints "completed OK!".

innobackupex version 2.4.4 based on MySQL server 5.7.13 Linux (x86_64) (revision id: df58cf2)
xtrabackup: cd to /data/backup/2018-11-28_18-50-47
xtrabackup: This target seems to be not prepared yet.
InnoDB: Number of pools: 1
．．．．．
InnoDB: 5.7.13 started; log sequence number 13741544981
xtrabackup: starting shutdown with innodb_fast_shutdown = 1
InnoDB: FTS optimize thread exiting.
InnoDB: Starting shutdown...
InnoDB: Shutdown completed; log sequence number 13741545378
181128 19:17:02 completed OK!

执行恢复：innobackupex提供了--copy-back参数，就是将指定的备份集，恢复到指定的路径下面（这个指定的路径是配置文件中datadir指定的路径）！

[[email protected] ~]# service mysqld stop       #首先停掉数据库
Shutting down MySQL.... SUCCESS! 
[[email protected] ~]# rm -fr /data/mysql/*      #情况datadir指定的目录，若是线上环境，确保一定备份过
[[email protected] ~]# innobackupex --copy-back /data/backup/2018-11-28_18-50-47/     #备份命令
181128 19:20:58 innobackupex: Starting the copy-back operation

IMPORTANT: Please check that the copy-back run completes successfully.
           At the end of a successful copy-back run innobackupex
           prints "completed OK!".

innobackupex version 2.4.4 based on MySQL server 5.7.13 Linux (x86_64) (revision id: df58cf2)
......
181128 19:21:30 [01] Copying ./xtrabackup_info to /data/mysql/xtrabackup_info
181128 19:21:30 [01]        ...done
181128 19:21:30 [01] Copying ./xtrabackup_binlog_pos_innodb to /data/mysql/xtrabackup_binlog_pos_innodb
181128 19:21:30 [01]        ...done
181128 19:21:30 [01] Copying ./xtrabackup_galera_info to /data/mysql/xtrabackup_galera_info
181128 19:21:30 [01]        ...done
181128 19:21:30 [01] Copying ./ibtmp1 to /data/mysql/ibtmp1
181128 19:21:30 [01]        ...done
181128 19:21:30 completed OK!        #恢复完成

数据库恢复之后，启动数据库：

[[email protected] ~]# chown -R mysql:mysql /data/mysql/
[[email protected] ~]# service mysqld start
Starting MySQL.. SUCCESS!

至此一个完全备份的数据恢复工作完成！

在使用innobackupex进行备份时，还可以使用--no-timestamp选项来阻止命令自动创建一个以时间命名的目录，我们可以自定义备份集的名字如下：

[[email protected] ~]# innobackupex --user=root --password=123456 --no-timestamp /data/backup/test_`date +%F`  #指定备份集的名字
[[email protected] ~]# cd /data/backup/
[[email protected] backup]# ls           #查看备份集
 test_2018-11-28
[[email protected] backup]#

有时候因为socket文件不在默认位置，可以使用--socket指定位置：

[[email protected] ~]# innobackupex --user=root --password="7abec53701c3eefb" --no-timestamp /data/backup/testdb
181128 19:40:10 innobackupex: Starting the backup operation

IMPORTANT: Please check that the backup run completes successfully.
           At the end of a successful backup run innobackupex
           prints "completed OK!".

181128 19:40:10  version_check Connecting to MySQL server with DSN ‘dbi:mysql:;mysql_read_default_group=xtrabackup‘ as ‘root‘  (using password: YES).
181128 19:40:10  version_check Connected to MySQL server
181128 19:40:10  version_check Executing a version check against the server...
181128 19:40:10  version_check Done.
181128 19:40:10 Connecting to MySQL server host: localhost, user: root, password: set, port: 0, socket: (null)
Failed to connect to MySQL server: Can‘t connect to local MySQL server through socket ‘/tmp/mysql.sock‘ (2).
[[email protected] ~]# innobackupex --user=root --password="7abec53701c3eefb" --no-timestamp --socket=/var/lib/mysql/mysql.sock  data/backup/testdb