數據備份與恢復 XtraBackup備份工具

數據備份與恢復
XtraBackup備份工具

1 數據備份與恢復
1.1 問題

本案例要求熟悉MySQL的備份與恢復，完成如下任務操做：

使用mysqldump備份數據庫
使用mysql 恢復數據庫

1.2 步驟

實現此案例須要按照以下步驟進行。

步驟一：使用mysqldump進行邏輯備份

1）備份MySQL服務器上的全部庫

將全部的庫備份爲mysql-all.sql文件：

[root@dbsvr1 ~]# mysqldump -u root -p --all-databases > /root/alldb.sql
Enter password:                                  //驗證口令
[root@dbsvr1 mysql]# file /root/alldb.sql          //確認備份文件類型
/root/alldb.sql: UTF-8 Unicode English text, with very long lines

查看備份文件alldb.sql的部份內容：

[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：若數據庫都使用MyISAM存儲引擎，能夠採用冷備份的方式，直接複製對應的數據庫目錄便可；恢復時從新複製回來就行。

2）只備份指定的某一個庫

將userdb庫備份爲userdb.sql文件：

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

查看備份文件userdb.sql的部份內容：

[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）同時備份指定的多個庫

同時備份mysql、userdb庫，保存爲mysql+userdb.sql文件：

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

查看備份文件userdb.sql的部份內容：

[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 */;

步驟二：使用mysql命令從備份中恢復數據庫、表

以恢復userdb庫爲例，可參考下列操做。一般不建議直接覆蓋舊庫，而是採用創建新庫並導入邏輯備份的方式執行恢復，待新庫正常後便可廢棄或刪除舊庫。

1）建立名爲userdb2的新庫

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

2）導入備份文件，在新庫中重建表及數據

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

3）確認新庫正常，啓用新庫

mysql> USE userdb2;                              //切換到新庫
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          //查詢數據，確承認用
    -> 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）廢棄或刪除舊庫

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

2 XtraBackup備份工具
2.1 問題

安裝XtraBackup軟件包。
使用XtraBackup執行完整備份、增量備份。
準備數據恢復目錄。

2.2 步驟

實現此案例須要按照以下步驟進行。

步驟一：安裝XtraBackup軟件包

1）瞭解軟件包描述信息

[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時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時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）安裝依賴包perl-DBD-MySQL perl-Digest-MD5 libev

使用RHEL 7自帶的便可，yum方式安裝：

[root@dbsvr1 pub]# yum -y install perl-DBD-MySQL perl-Digest-MD5
libev使用網上找的rpm包 libev-4.15-1.el6.rf.x86_64.rpm //該包由講師提供
[root@dbsvr1 pub]#rpm –ivh libev-4.15-1.el6.rf.x86_64.rpm

若是未安裝這些依賴包，則直接安裝percona-xtrabackup時會報錯：

代碼

3）安裝percona-xtrabackup

[root@dbsvr1 pub]#rpm -ivh percona-xtrabackup-*.rpm
警告：percona-xtrabackup-24-2.4.6-2.el7.x86_64.rpm: 頭V4 DSA/SHA1 Signature, 密鑰 ID cd2efd2a: NOKEY
準備中...                          ################################# [100%]
正在升級/安裝...
   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）確認安裝的主要程序/腳本

[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

步驟二：使用XtraBackup執行數據庫備份

--host 主機名

--port 3306

--user 用戶名

--password 密碼

--databases="庫名"

--databases="庫1 庫2"

--databases="庫.表"

--no-timestamp 不用日期命名備份文件存儲的子目錄，使用備份的數據庫名作備份目錄名

--no-timestmap 不使用日期命名備份目錄名

1）作一個完整備份

默認狀況下，備份文件存儲的子目錄會用日期命名，

innobackupex做爲客戶端工具，以mysql協議連入mysqld，將數據備份到/backup文件夾：

[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

確認備份好的文件數據：

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

2）作一個增量備份（基於前一步的完整備份）

隨意作一些新增或更改庫表的操做，好比在db1庫中新建一個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)

之前一次保存到/backup的完整備份爲基礎，作一個增量備份，保存到/incr01/，指定增量備份參照的基本目錄（完整備份目錄）須要用到選項--incremental-basedir。相關操做以下：

[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!

確認備份好的文件數據：

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

對比完整備份、增量備份的大小：

[root@dbsvr1 ~]# du -sh /backup/ /incr01/
142M    /backup/                              //完整備份的大小
3.5M    /incr01/                              //增量備份的大小

步驟三：準備用於恢復的數據庫目錄

經過XtraBackup工具有份的數據庫目錄，若要恢復到另外一個MySQL服務器，須要先作一個「--apply-log --redo-only 」的準備操做。

1）準備恢復「完整備份」

完成準備之後，最終/backup可用來重建MySQL服務器。這種狀況下，須要先作一個「--apply-log --redo-only 」的準備操做，以確保數據一致性：

[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!

準備恢復「增量備份」

[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）關閉mysql服務，並將/var/lib/mysql/下的文件刪除，假設數據被刪除。

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

3）恢復「完整備份+增量備份」

完成準備之後，最終仍然是/backup用來重建MySQL服務器，但這種狀況下需提早合併相關增量備份的數據

[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/下文件屬主與屬組,查看數據：

恢復後，/var/lib/mysql下文件屬組與屬主皆爲root，須要更改成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   |
+------+------+