数据备份与恢复
XtraBackup备份工具

1 数据备份与恢复
1.1 问题

本案例要求熟悉MySQL的备份与恢复,完成以下任务操作:

使用mysqldump备份数据库
使用mysql 恢复数据库

1.2 步骤

实现此案例需要按照如下步骤进行。

步骤一:使用mysqldump进行逻辑备份

1)备份MySQL服务器上的所有库

将所有的库备份为mysql-all.sql文件:

[root@dbsvr1 ~]# mysqldump -u root -p --all-databases > /root/alldb.sql
Enter password:                                  //验证口令
[root@dbsvr1 mysql]# file /root/alldb.sql          //确认备份文件类型
/root/alldb.sql: UTF-8 Unicode English text, with very long lines

查看备份文件alldb.sql的部分内容:

[root@dbsvr1 ~]# grep -vE '^/|^-|^$' /root/alldb.sql | head -15
CREATE DATABASE /*!32312 IF NOT EXISTS*/ `home` /*!40100 DEFAULT CHARACTER SET latin1 */;
USE `home`;
DROP TABLE IF EXISTS `biao01`;
CREATE TABLE `biao01` (
  `id` int(2) NOT NULL,
  `name` varchar(8) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
LOCK TABLES `biao01` WRITE;
UNLOCK TABLES;
DROP TABLE IF EXISTS `biao02`;
CREATE TABLE `biao02` (
  `id` int(4) NOT NULL,
  `name` varchar(8) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
.. ..

注意:若数据库都使用MyISAM存储引擎,可以采用冷备份的方式,直接复制对应的数据库目录即可;恢复时重新复制回来就行。

2)只备份指定的某一个库

将userdb库备份为userdb.sql文件:

[root@dbsvr1 ~]# mysqldump -u root -p userdb > userdb.sql
Enter password:                                  //验证口令

查看备份文件userdb.sql的部分内容:

[root@dbsvr1 ~]# grep -vE '^/|^-|^$' /root/userdb.sql
DROP TABLE IF EXISTS `stu_info`;
CREATE TABLE `stu_info` (
  `name` varchar(12) NOT NULL,
  `gender` enum('boy','girl') DEFAULT 'boy',
  `age` int(3) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
LOCK TABLES `stu_info` WRITE;
.. ..

3)同时备份指定的多个库

同时备份mysql、userdb库,保存为mysql+userdb.sql文件:

[root@dbsvr1 ~]# mysqldump -u root -p -B mysql  userdb > mysql+test+userdb.sql
Enter password:                                  //验证口令

查看备份文件userdb.sql的部分内容:

[root@dbsvr1 ~]# grep '^CREATE DATA' /root/mysql+userdb.sql
CREATE DATABASE /*!32312 IF NOT EXISTS*/ `mysql` /*!40100 DEFAULT CHARACTER SET latin1 */;
CREATE DATABASE /*!32312 IF NOT EXISTS*/ `userdb` /*!40100 DEFAULT CHARACTER SET latin1 */;

步骤二:使用mysql命令从备份中恢复数据库、表

以恢复userdb库为例,可参考下列操作。通常不建议直接覆盖旧库,而是采用建立新库并导入逻辑备份的方式执行恢复,待新库正常后即可废弃或删除旧库。

1)创建名为userdb2的新库

mysql> CREATE DATABASE userdb2;
Query OK, 1 row affected (0.00 sec)

2)导入备份文件,在新库中重建表及数据

[root@dbsvr1 ~]# mysql -u root -p userdb2 < /root/userdb.sql
Enter password:                                  //验证口令

3)确认新库正常,启用新库

mysql> USE userdb2;                              //切换到新库
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> SELECT sn,username,uid,gid,homedir          //查询数据,确认可用
    -> FROM userlist LIMIT 10;
+----+----------+-----+-----+-----------------+
| sn | username | uid | gid | homedir         |
+----+----------+-----+-----+-----------------+
|  1 | root     |   0 |   0 | /root           |
|  2 | bin      |   1 |   1 | /bin            |
|  3 | daemon   |   2 |   2 | /sbin           |
|  4 | adm      |   3 |   4 | /var/adm        |
|  5 | lp       |   4 |   7 | /var/spool/lpd  |
|  6 | sync     |   5 |   0 | /sbin           |
|  7 | shutdown |   6 |   0 | /sbin           |
|  8 | halt     |   7 |   0 | /sbin           |
|  9 | mail     |   8 |  12 | /var/spool/mail |
| 10 | operator |  11 |   0 | /root           |
+----+----------+-----+-----+-----------------+
10 rows in set (0.00 sec)

4)废弃或删除旧库

mysql> DROP DATABASE userdb;
Query OK, 2 rows affected (0.09 sec)

2 XtraBackup备份工具
2.1 问题

安装XtraBackup软件包。
使用XtraBackup执行完整备份、增量备份。
准备数据恢复目录。

2.2 步骤

实现此案例需要按照如下步骤进行。

步骤一:安装XtraBackup软件包

1)了解软件包描述信息

[root@dbsvr1 pub]# rpm -qpi percona-xtrabackup-24-2.4.6-2.el7.x86_64.rpm
Name        : percona-xtrabackup-24
Version     : 2.4.6
Release     : 2.el7
Architecture: x86_64
Install Date: (not installed)
Group       : Applications/Databases
Size        : 32416340
License     : GPLv2
Signature   : DSA/SHA1, 2017年02月27日 星期一 20时28分17秒, Key ID 1c4cbdcdcd2efd2a
Source RPM  : percona-xtrabackup-24-2.4.6-2.el7.src.rpm
Build Date  : 2017年02月27日 星期一 20时27分21秒
Build Host  : vps-centos7-x64-01.ci.percona.com
Relocations : (not relocatable)
URL         : http://www.percona.com/software/percona-xtrabackup
Summary     : XtraBackup online backup for MySQL / InnoDB
Description :
Percona XtraBackup is OpenSource online (non-blockable) backup solution for InnoDB and XtraDB engines

2)安装依赖包perl-DBD-MySQL perl-Digest-MD5 libev

使用RHEL 7自带的即可,yum方式安装:

[root@dbsvr1 pub]# yum -y install perl-DBD-MySQL perl-Digest-MD5
libev使用网上找的rpm包 libev-4.15-1.el6.rf.x86_64.rpm //该包由讲师提供
[root@dbsvr1 pub]#rpm –ivh libev-4.15-1.el6.rf.x86_64.rpm

如果未安装这些依赖包,则直接安装percona-xtrabackup时会报错:

代码

3)安装percona-xtrabackup

[root@dbsvr1 pub]#rpm -ivh percona-xtrabackup-*.rpm
警告:percona-xtrabackup-24-2.4.6-2.el7.x86_64.rpm: 头V4 DSA/SHA1 Signature, 密钥 ID cd2efd2a: NOKEY
准备中...                          ################################# [100%]
正在升级/安装...
   1:percona-xtrabackup-24-2.4.6-2.el7################################# [ 33%]
   2:percona-xtrabackup-test-24-2.4.6-################################# [ 67%]
   3:percona-xtrabackup-24-debuginfo-2################################# [100%]

4)确认安装的主要程序/脚本

[root@dbsvr1 pub]# rpm -ql percona-xtrabackup-24-2.4.6-2.el7.x86_64
/usr/bin/innobackupex
/usr/bin/xbcloud
/usr/bin/xbcloud_osenv
/usr/bin/xbcrypt
/usr/bin/xbstream
/usr/bin/xtrabackup
/usr/share/doc/percona-xtrabackup-24-2.4.6
/usr/share/doc/percona-xtrabackup-24-2.4.6/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

步骤二:使用XtraBackup执行数据库备份

--host 主机名

--port 3306

--user 用户名

--password 密码

--databases="库名"

--databases="库1 库2"

--databases="库.表"

--no-timestamp 不用日期命名备份文件存储的子目录,使用备份的数据库名做备份目录名

--no-timestmap 不使用日期命名备份目录名

1)做一个完整备份

默认情况下,备份文件存储的子目录会用日期命名,

innobackupex作为客户端工具,以mysql协议连入mysqld,将数据备份到/backup文件夹:

[root@dbsvr1 ~]# innobackupex --user=root --password=1234567 /backup/mysql –no-timestamp
170425 11:05:44 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!".
Unrecognized character \x01; marked by <-- HERE after <-- HERE near column 1 at - line 1374.
170425 11:05:45 Connecting to MySQL server host: localhost, user: root, password: set, port: not set, socket: not set
Using server version 5.7.17
innobackupex version 2.4.6 based on MySQL server 5.7.13 Linux (x86_64) (revision id: 8ec05b7)
xtrabackup: uses posix_fadvise().
xtrabackup: cd to /var/lib/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
170425 11:05:45 >> log scanned up to (2543893)
xtrabackup: Generating a list of tablespaces
InnoDB: Allocated tablespace ID 2 for mysql/plugin, old maximum was 0
170425 11:05:45 [01] Copying ./ibdata1 to /backup/ibdata1
170425 11:05:45 [01]        ...done
170425 11:05:46 [01] Copying ./mysql/plugin.ibd to /backup/mysql/plugin.ibd
170425 11:05:46 [01]        ...done
170425 11:05:46 [01] Copying ./mysql/servers.ibd to /backup/mysql/servers.ibd
170425 11:05:46 [01]        ...done
170425 11:05:46 [01] Copying ./mysql/help_topic.ibd to /backup/mysql/help_topic.ibd
170425 11:05:46 [01]        ...done
170425 11:05:46 >> log scanned up to (2543893)
.. ..
170425 11:06:00 [01] Copying ./sys/x@0024waits_global_by_latency.frm to /backup/sys/x@0024waits_global_by_latency.frm
170425 11:06:00 [01]        ...done
170425 11:06:00 [01] Copying ./sys/session_ssl_status.frm to /backup/sys/session_ssl_status.frm
170425 11:06:00 [01]        ...done
170425 11:06:00 [01] Copying ./db1/db.opt to /backup/db1/db.opt
170425 11:06:00 [01]        ...done
170425 11:06:00 [01] Copying ./db1/tb1.frm to /backup/db1/tb1.frm
170425 11:06:00 [01]        ...done
170425 11:06:00 Finished backing up non-InnoDB tables and files
170425 11:06:00 Executing FLUSH NO_WRITE_TO_BINLOG ENGINE LOGS...
xtrabackup: The latest check point (for incremental): '2543884'
xtrabackup: Stopping log copying thread.
.170425 11:06:00 >> log scanned up to (2543893)
170425 11:06:00 Executing UNLOCK TABLES
170425 11:06:00 All tables unlocked
170425 11:06:00 [00] Copying ib_buffer_pool to /backup/ib_buffer_pool
170425 11:06:00 [00]        ...done
170425 11:06:00 Backup created in directory '/backup/'
170425 11:06:00 [00] Writing backup-my.cnf
170425 11:06:00 [00]        ...done
170425 11:06:00 [00] Writing xtrabackup_info
170425 11:06:00 [00]        ...done
xtrabackup: Transaction log of lsn (2543884) to (2543893) was copied.
170425 11:06:01 completed OK

确认备份好的文件数据:

[root@dbsvr1 ~]#ls /backup/
backup-my.cnf  ib_buffer_pool  mysql      sys                   xtrabackup_info
db1  ibdata1      performance_schema  xtrabackup_checkpoints  xtrabackup_logfile

2)做一个增量备份(基于前一步的完整备份)

随意做一些新增或更改库表的操作,比如在db1库中新建一个mytb的表:

mysql> USE db1;
Database changed
mysql> CREATE TABLE mytb(id int(4), name varchar(24));
Query OK, 0 rows affected (0.38 sec)
mysql> INSERT INTO tb1 VALUES
    -> (1,'bon'),
    -> (2,'bo'),
Query OK, 2 rows affected (0.12 sec)
Records: 2  Duplicates: 0  Warnings: 0
mysql> SELECT * FROM tb1;
+------+------+
| id   | name |
+------+------+
|    1 | bob  |
|    2 | bo   |
+------+------+
2 rows in set (0.00 sec)

以前一次保存到/backup的完整备份为基础,做一个增量备份,保存到/incr01/,指定增量备份参照的基本目录(完整备份目录)需要用到选项--incremental-basedir。相关操作如下:

[root@dbsvr1 ~]# innobackupex  --user=root --password=12345678 --incremental /incr01 --incremental-basedir=/backup/ --no-timestamp
170425 11:30:14 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!".
Unrecognized character \x01; marked by <-- HERE after <-- HERE near column 1 at - line 1374.
170425 11:30:14 Connecting to MySQL server host: localhost, user: root, password: set, port: not set, socket: not set
Using server version 5.7.17
innobackupex version 2.4.6 based on MySQL server 5.7.13 Linux (x86_64) (revision id: 8ec05b7)
incremental backup from 2543884 is enabled.
xtrabackup: uses posix_fadvise().
xtrabackup: cd to /var/lib/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
170425 11:30:14 >> log scanned up to (2549933)
xtrabackup: Generating a list of tablespaces
InnoDB: Allocated tablespace ID 2 for mysql/plugin, old maximum was 0
xtrabackup: using the full scan for incremental backup
170425 11:30:15 [01] Copying ./ibdata1 to /incr01/ibdata1.delta
170425 11:30:15 [01]        ...done
170425 11:30:15 >> log scanned up to (2549933)
170425 11:30:15 [01] Copying ./mysql/plugin.ibd to /incr01/mysql/plugin.ibd.delta
170425 11:30:15 [01]        ...done
... ...
170425 11:30:35 Executing UNLOCK TABLES
170425 11:30:35 All tables unlocked
170425 11:30:35 [00] Copying ib_buffer_pool to /incr01/ib_buffer_pool
170425 11:30:35 [00]        ...done
170425 11:30:35 Backup created in directory '/incr01/'
170425 11:30:35 [00] Writing backup-my.cnf
170425 11:30:35 [00]        ...done
170425 11:30:35 [00] Writing xtrabackup_info
170425 11:30:35 [00]        ...done
xtrabackup: Transaction log of lsn (2549924) to (2549933) was copied.
170425 11:30:35 completed OK!

确认备份好的文件数据:

[root@dbsvr1 ~]# ls /incr01/
backup-my.cnf  ib_buffer_pool  ibdata1.meta  performance_schema  xtrabackup_checkpoints  xtrabackup_logfile
db1            ibdata1.delta   mysql         sys 

对比完整备份、增量备份的大小:

[root@dbsvr1 ~]# du -sh /backup/ /incr01/
142M    /backup/                              //完整备份的大小
3.5M    /incr01/                              //增量备份的大小

步骤三:准备用于恢复的数据库目录

通过XtraBackup工具备份的数据库目录,若要恢复到另一个MySQL服务器,需要先做一个“--apply-log --redo-only ”的准备操作。

1)准备恢复“完整备份”

完成准备以后,最终/backup可用来重建MySQL服务器。这种情况下,需要先做一个“--apply-log --redo-only ”的准备操作,以确保数据一致性:

[root@dbsvr1 ~]#innobackupex  --user=root --password=12345678 --apply-log  --redo-only /backup/
170425 11:42:19 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 2.4.6 based on MySQL server 5.7.13 Linux (x86_64) (revision id: 8ec05b7)
xtrabackup: cd to /backup/
xtrabackup: This target seems to be already prepared.
InnoDB: Number of pools: 1
xtrabackup: notice: xtrabackup_logfile was already used to '--prepare'.
xtrabackup: using the following InnoDB configuration for recovery:
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
xtrabackup: using the following InnoDB configuration for recovery:
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
xtrabackup: Starting InnoDB instance for recovery.
xtrabackup: Using 104857600 bytes for buffer pool (set by --use-memory parameter)
InnoDB: PUNCH HOLE support available
InnoDB: Mutexes and rw_locks use GCC atomic builtins
InnoDB: Uses event mutexes
InnoDB: GCC builtin __atomic_thread_fence() is used for memory barrier
InnoDB: Compressed tables use zlib 1.2.7
InnoDB: Number of pools: 1
InnoDB: Not using CPU crc32 instructions
InnoDB: Initializing buffer pool, total size = 100M, instances = 1, chunk size = 100M
InnoDB: Completed initialization of buffer pool
InnoDB: page_cleaner coordinator priority: -20
InnoDB: Highest supported file format is Barracuda.
xtrabackup: starting shutdown with innodb_fast_shutdown = 1
InnoDB: Starting shutdown...
InnoDB: Shutdown completed; log sequence number 2544177
InnoDB: Number of pools: 1
170425 11:42:20 completed OK!

准备恢复“增量备份”

[root@dbsvr1 ~]#innobackupex  --user=root --password=12345678 --apply-log  --redo-only /backup/  --incremental-dir=/incr01
170425 11:42:55 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 2.4.6 based on MySQL server 5.7.13 Linux (x86_64) (revision id: 8ec05b7)
incremental backup from 2543884 is enabled.
xtrabackup: cd to /backup/
xtrabackup: This target seems to be already prepared with --apply-log-only.
InnoDB: Number of pools: 1
xtrabackup: xtrabackup_logfile detected: size=8388608, start_lsn=(2549924)
xtrabackup: using the following InnoDB configuration for recovery:
xtrabackup:   innodb_data_home_dir = .
xtrabackup:   innodb_data_file_path = ibdata1:12M:autoextend
xtrabackup:   innodb_log_group_home_dir = /incr01/
xtrabackup:   innodb_log_files_in_group = 1
xtrabackup:   innodb_log_file_size = 8388608
xtrabackup: Generating a list of tablespaces
InnoDB: Allocated tablespace ID 2 for mysql/plugin, old maximum was 0
xtrabackup: page size for /incr01//ibdata1.delta is 16384 bytes
Applying /incr01//ibdata1.delta to ./ibdata1...
... ...
170425 11:43:09 [01] Copying /incr01/performance_schema/global_status.frm to ./performance_schema/global_status.frm
170425 11:43:09 [01]        ...done
170425 11:43:09 [01] Copying /incr01/performance_schema/session_status.frm to ./performance_schema/session_status.frm
170425 11:43:09 [01]        ...done
170425 11:43:09 [00] Copying /incr01//xtrabackup_info to ./xtrabackup_info
170425 11:43:09 [00]        ...done
170425 11:43:10 completed OK!

2)关闭mysql服务,并将/var/lib/mysql/下的文件删除,假设数据被删除。

[root@dbsvr1 ~]#systemctl  stop  mysqld
[root@dbsvr1 ~]#rm -rf /var/lib/mysql

3)恢复“完整备份+增量备份”

完成准备以后,最终仍然是/backup用来重建MySQL服务器,但这种情况下需提前合并相关增量备份的数据

[root@dbsvr1 ~]# innobackupex --user=root --password=12345678 --copy-back  /backup/
... ...
170425 11:51:39 [01] Copying ./performance_schema/global_status.frm to /var/lib/mysql/performance_schema/glo.frm
170425 11:51:39 [01]        ...done
170425 11:51:39 [01] Copying ./performance_schema/session_status.frm to /var/lib/mysql/performance_schema/seus.frm
170425 11:51:39 [01]        ...done
170425 11:51:39 [01] Copying ./ib_buffer_pool to /var/lib/mysql/ib_buffer_pool
170425 11:51:39 [01]        ...done
170425 11:51:39 [01] Copying ./ibtmp1 to /var/lib/mysql/ibtmp1
170425 11:51:39 [01]        ...done
170425 11:51:39 [01] Copying ./xtrabackup_info to /var/lib/mysql/xtrabackup_info
170425 11:51:39 [01]        ...done
170425 11:51:39 completed OK!

4)修改/var/lib/mysql/下文件属主与属组,查看数据:

恢复后,/var/lib/mysql下文件属组与属主皆为root,需要更改为mysql

[root@dbsvr1 ~]#chown -R mysql:mysql /var/lib/mysql
[root@dbsvr1 ~]#systemctl  start mysqld.service 
[root@dbsvr1 ~]#mysql -uroot -p12345678 -e "select * from db1.tb1"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------+------+
| id   | name |
+------+------+
|    1 | bob  |
|    2 | bo   |
+------+------+