xtrabackup 詳解

xtrabackup是Percona公司CTO Vadim參與開發的一款基於InnoDB的在線熱備工具,具備開源,免費,支持在線熱備,備份恢復速度快,佔用磁盤空間小等特色,而且支持不一樣狀況下的多種備份形式。xtrabackup的官方下載地址爲http://www.percona.com/software/percona-xtrabackuphtml

xtrabackup包含兩個主要的工具,即xtrabackup和innobackupex,兩者區別以下:mysql

(1)xtrabackup只能備份innodb和xtradb兩種引擎的表,而不能備份myisam引擎的表;sql

(2)innobackupex是一個封裝了xtrabackup的Perl腳本,支持同時備份innodb和myisam,但在對myisam備份時須要加一個全局的讀鎖。還有就是myisam不支持增量備份數據庫

1.備份過程安全

innobackupex備份過程以下圖:服務器

                                                                                (圖1 innobackupex備份過程,本文中全部圖都是google所得)app

在圖1中,備份開始時首先會開啓一個後臺檢測進程,實時檢測mysql redo的變化,一旦發現redo中有新的日誌寫入,馬上將日誌記入後臺日誌文件xtrabackup_log中。以後複製innodb的數據文件和系統表空間文件ibdata1,待複製結束後,執行flush tables with read lock操做,複製.frm,MYI,MYD,等文件(執行flush tableswith read lock的目的是爲了防止數據表發生DDL操做,而且在這一時刻得到binlog的位置)最後會發出unlock tables,把表設置爲可讀可寫狀態,最終中止xtrabackup_log。ssh

2.全備恢復socket

這一階段會啓動xtrabackup內嵌的innodb實例,回放xtrabackup日誌xtrabackup_log,將提交的事務信息變動應用到innodb數據/表空間,同時回滾未提交的事務(這一過程相似innodb的實例恢復)。恢復過程以下圖:ide

                                                       (圖2 innobackupex 恢復過程)

3.增量備份

innobackupex增量備份過程當中的"增量"處理,其實主要是相對innodb而言,對myisam和其餘存儲引擎而言,它仍然是全拷貝(全備份)

"增量"備份的過程主要是經過拷貝innodb中有變動的"頁"(這些變動的數據頁指的是"頁"的LSN大於xtrabackup_checkpoints中給定的LSN)。增量備份是基於全備的,第一次增備的數據必需要基於上一次的全備,以後的每次增備都是基於上一次的增備,最終達到一致性的增備。增量備份的過程以下,和全備的過程很相似,區別僅在第2步。

                                                                            ( 圖 3 innobackupex增量備份過程)

4.增量備份恢復

和全備恢復相似,也須要兩步,一是數據文件的恢復,如圖4,這裏的數據來源由3部分組成:全備份,增量備份和xtrabackup log。二是對未提交事務的回滾,如圖5所示:

                                                   ( 圖4 innobackupex 增量備份恢復過程1)

       ( 圖5 innobackupex增量備份恢復過程2)

 

5.innobackupex使用示例

(1)安裝使用xtrabackup,安裝比較簡單,咱們使用二進制編譯好的就好了,這種工具無需源碼編譯,由於沒有什麼功能須要俺們定製。

[root@MySQL-01 ~]# wget http://www.percona.com/redir/downloads/XtraBackup/LATEST/binary/Linux/x86_64/percona-xtrabackup-2.1.8-733-Linux-x86_64.tar.gz 
[root@MySQL-01 ~]# tar xf percona-xtrabackup-2.1.8-733-Linux-x86_64.tar.gz -C /usr/local/
[root@MySQL-01 ~]# mv /usr/local/percona-xtrabackup-2.1.8-Linux-x86_64/ /usr/local/xtrabackup
[root@MySQL-01 ~]# echo "export PATH=\$PATH:/usr/local/xtrabackup/bin" >> /etc/profile
[root@MySQL-01 ~]# source /etc/profile
[root@MySQL-01 ~]# 

(2)全量備份

建立備份用戶:

mysql> create user 'backup'@'%' identified by 'yayun';
Query OK, 0 rows affected (0.01 sec)

mysql> grant reload,lock tables,replication client,create tablespace,super on *.* to 'backup'@'%';
Query OK, 0 rows affected (0.00 sec)

mysql> 

進行全備份

備份數據存放在/data/backup/下面,innobackupex會自動建立一個文件夾,是當前系統的時間戳

mysql> select * from yayun.t1;
+------+-------+
| id   | name  |
+------+-------+
|    1 | yayun |
|    2 | atlas |
+------+-------+
2 rows in set (0.00 sec)

mysql> 

測試數據就是yayun庫中的t1表

[root@MySQL-01 ~]# innobackupex --user=backup --password=yayun --socket=/tmp/mysqld.sock --defaults-file=/etc/my.cnf /data/backup/
xtrabackup: Creating suspend file '/data/backup/2014-04-07_23-05-04/xtrabackup_log_copied' with pid '57608'
xtrabackup: Transaction log of lsn (5324782783) to (5324782783) was copied.
140407 23:06:14  innobackupex: All tables unlocked
innobackupex: Backup created in directory '/data/backup/2014-04-07_23-05-04'
innobackupex: MySQL binlog position: filename 'mysql-bin.000014', position 2983
140407 23:06:14  innobackupex: Connection to database server closed
140407 23:06:14  innobackupex: completed OK!
[root@MySQL-01 ~]# 

上面的過程當中處理過,主要看最後是否提示innobackupex completed ok,能夠看見備份成功。咱們看看/data/backup目錄下產生了什麼

[root@MySQL-01 backup]# pwd
/data/backup
[root@MySQL-01 backup]# ll
total 4
drwxr-xr-x 12 root root 4096 Apr  7 23:06 2014-04-07_23-05-04
[root@MySQL-01 backup]# cd 2014-04-07_23-05-04/
[root@MySQL-01 2014-04-07_23-05-04]# ll
total 845888
-rw-r--r-- 1 root root       261 Apr  7 23:05 backup-my.cnf
drwx------ 2 root root      4096 Apr  7 23:06 employees
drwx------ 2 root root      4096 Apr  7 23:06 host
-rw-r----- 1 root root 866123776 Apr  7 23:05 ibdata1
drwx------ 2 root root      4096 Apr  7 23:06 menagerie
drwxr-xr-x 2 root root      4096 Apr  7 23:06 mysql
drwxr-xr-x 2 root root      4096 Apr  7 23:06 performance_schema
drwx------ 2 root root      4096 Apr  7 23:06 sakila
drwx------ 2 root root      4096 Apr  7 23:06 test
drwx------ 2 root root      4096 Apr  7 23:06 world_innodb
drwxr-xr-x 2 root root      4096 Apr  7 23:06 world_myisam
-rw-r--r-- 1 root root        13 Apr  7 23:06 xtrabackup_binary
-rw-r--r-- 1 root root        24 Apr  7 23:06 xtrabackup_binlog_info
-rw-r----- 1 root root        95 Apr  7 23:06 xtrabackup_checkpoints
-rw-r----- 1 root root      2560 Apr  7 23:06 xtrabackup_logfile
drwx------ 2 root root      4096 Apr  7 23:06 yayun
[root@MySQL-01 2014-04-07_23-05-04]# 

能夠看見有對應數據庫的名字,好比yayun,還有一個以時間戳命名的目錄。咱們看看對應文件裏面的內容,這幾個比較重要

[root@MySQL-01 2014-04-07_23-05-04]# cat xtrabackup_checkpoints 
backup_type = full-backuped
from_lsn = 0
to_lsn = 5324782783
last_lsn = 5324782783
compact = 0
[root@MySQL-01 2014-04-07_23-05-04]# cat xtrabackup_binlog_info 
mysql-bin.000014        2983
[root@MySQL-01 2014-04-07_23-05-04]# 

能夠看見相關文件記錄了LSN,日誌偏移量,還能夠看見此次是全備份,相信聰明的童鞋們一眼就看懂了。^_^

刪除數據庫,而後恢復全備(線上不要這樣搞

mysql> drop database yayun;
Query OK, 1 row affected (0.04 sec)

mysql> 

恢復全備

恢復備份到mysql的數據文件目錄,這一過程要先關閉mysql數據庫,重命名或者刪除原數據文件目錄均可以,再建立一個新的數據文件目錄,將備份數據複製到新的數據文件目錄下,賦權,修改權限,啓動數據庫

[root@MySQL-01 ~]# /etc/init.d/mysqld stop
Shutting down MySQL.....                                   [  OK  ]
[root@MySQL-01 ~]# mv /data/mysql /data/mysql_bak
[root@MySQL-01 ~]# mkdir /data/mysql
[root@MySQL-01 ~]# 
[root@MySQL-01 ~]# innobackupex --apply-log /data/backup/2014-04-07_23-05-04/ 
xtrabackup: starting shutdown with innodb_fast_shutdown = 1
140407 23:22:36  InnoDB: Starting shutdown...
140407 23:22:40  InnoDB: Shutdown completed; log sequence number 5324784140
140407 23:22:40  innobackupex: completed OK!

以上對應的目錄就是innobackupex全備份本身建立的目錄。

[root@MySQL-01 ~]# innobackupex --defaults-file=/etc/my.cnf --copy-back --rsync /data/backup/2014-04-07_23-05-04/
innobackupex: Starting to copy InnoDB log files
innobackupex: in '/data/backup/2014-04-07_23-05-04'
innobackupex: back to original InnoDB log directory '/data/mysql'
innobackupex: Copying '/data/backup/2014-04-07_23-05-04/ib_logfile1' to '/data/mysql/ib_logfile1'
innobackupex: Copying '/data/backup/2014-04-07_23-05-04/ib_logfile0' to '/data/mysql/ib_logfile0'
innobackupex: Finished copying back files.
140407 23:27:38  innobackupex: completed OK!
[root@MySQL-01 ~]# 

能夠看見已經成功恢復,修改數據目錄權限,啓動mysql,效驗數據是否正常,查看yayun庫下面的t1表中的數據。

[root@MySQL-01 ~]# chown -R mysql.mysql /data/mysql
[root@MySQL-01 ~]# /etc/init.d/mysqld start
Starting MySQL.................                            [  OK  ]
[root@MySQL-01 ~]# 
mysql> use yayun
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 * from t1;
+------+-------+
| id   | name  |
+------+-------+
|    1 | yayun |
|    2 | atlas |
+------+-------+
2 rows in set (0.00 sec)

mysql> 

發現數據已經成功恢復。

(3)增量備份

在進行增量備份時,首先要進行一次全量備份,第一次增量備份是基於全備的,以後的增量備份是基於上一次的增量備份,以此類推。

全備份放在/data/backup/full,增量備份放在/data/backup/incremental

[root@MySQL-01 ~]# tree /data/backup/
/data/backup/
├── full
└── incremental

2 directories, 0 files
[root@MySQL-01 ~]# 

廢話少說,我們先來一次全備份

[root@MySQL-01 ~]# innobackupex --user=backup --password=yayun --socket=/tmp/mysqld.sock --defaults-file=/etc/my.cnf /data/backup/full/
innobackupex: Backup created in directory '/data/backup/full/2014-04-07_23-37-20'
innobackupex: MySQL binlog position: filename 'mysql-bin.000001', position 107
140407 23:38:29  innobackupex: Connection to database server closed
140407 23:38:29  innobackupex: completed OK!
[root@MySQL-01 ~]# 

爲了測試效果,咱們在t1表中插入數據

mysql> select * from t1;
+------+-------+
| id   | name  |
+------+-------+
|    1 | yayun |
|    2 | atlas |
+------+-------+
2 rows in set (0.00 sec)

mysql> insert into t1 select 1,'love sql';
Query OK, 1 row affected (0.01 sec)
Records: 1  Duplicates: 0  Warnings: 0

mysql> select * from t1;                  
+------+----------+
| id   | name     |
+------+----------+
|    1 | yayun    |
|    2 | atlas    |
|    1 | love sql |
+------+----------+
3 rows in set (0.00 sec)

mysql> 

如今來一次增量備份1

[root@MySQL-01 ~]# innobackupex --user=backup --password=yayun --socket=/tmp/mysqld.sock --defaults-file=/etc/my.cnf --incremental /data/backup/incremental/ --incremental-basedir=/data/backup/full/2014-04-07_23-37-20/ --parallel=2
innobackupex: Backup created in directory '/data/backup/incremental/2014-04-07_23-42-46'
innobackupex: MySQL binlog position: filename 'mysql-bin.000001', position 301
140407 23:43:25  innobackupex: Connection to database server closed
140407 23:43:25  innobackupex: completed OK!
[root@MySQL-01 ~]# 

咱們看看增量備份的大小以及文件內容

[root@MySQL-01 ~]# du -sh /data/backup/full/2014-04-07_23-37-20/
1.2G    /data/backup/full/2014-04-07_23-37-20/
[root@MySQL-01 ~]# du -sh /data/backup/incremental/2014-04-07_23-42-46/
3.6M    /data/backup/incremental/2014-04-07_23-42-46/
[root@MySQL-01 ~]# 

看見增量備份的數據很小吧,就是備份改變的數據而已。

[root@MySQL-01 2014-04-07_23-42-46]# pwd
/data/backup/incremental/2014-04-07_23-42-46
[root@MySQL-01 2014-04-07_23-42-46]# cat xtrabackup_checkpoints 
backup_type = incremental
from_lsn = 5324784718
to_lsn = 5324785066
last_lsn = 5324785066
compact = 0
[root@MySQL-01 2014-04-07_23-42-46]# 

上面已經明顯說明是增量備份了,該工具很人性化吧,呵呵

咱們再次向t1表插入數據,而後建立增量備份2

mysql> select * from t1;
+------+----------+
| id   | name     |
+------+----------+
|    1 | yayun    |
|    2 | atlas    |
|    1 | love sql |
+------+----------+
3 rows in set (0.00 sec)

mysql> insert into t1 select 1,'mysql dba';
Query OK, 1 row affected (0.00 sec)
Records: 1  Duplicates: 0  Warnings: 0

mysql> select * from t1;                   
+------+-----------+
| id   | name      |
+------+-----------+
|    1 | yayun     |
|    2 | atlas     |
|    1 | love sql  |
|    1 | mysql dba |
+------+-----------+
4 rows in set (0.00 sec)

mysql> 

建立增量備份2(此次是基於上次的增量備份哦)

[root@MySQL-01 ~]# innobackupex --user=backup --password=yayun --socket=/tmp/mysqld.sock --defaults-file=/etc/my.cnf --incremental /data/backup/incremental/ --incremental-basedir=/data/backup/incremental/2014-04-07_23-42-46/ --parallel=2
innobackupex: Backup created in directory '/data/backup/incremental/2014-04-07_23-51-15'
innobackupex: MySQL binlog position: filename 'mysql-bin.000001', position 496
140407 23:51:55  innobackupex: Connection to database server closed
140407 23:51:55  innobackupex: completed OK!
[root@MySQL-01 ~]# 
[root@MySQL-01 ~]# ls -ltr /data/backup/full/
total 4
drwxr-xr-x 12 root root 4096 Apr  7 23:38 2014-04-07_23-37-20
[root@MySQL-01 ~]# ls -ltr /data/backup/incremental/
total 8
drwxr-xr-x 12 root root 4096 Apr  7 23:43 2014-04-07_23-42-46
drwxr-xr-x 12 root root 4096 Apr  7 23:51 2014-04-07_23-51-15
[root@MySQL-01 ~]# 

(4)增量備份恢復

增量備份的恢復大致爲3個步驟

*恢復徹底備份

*恢復增量備份到徹底備份(開始恢復的增量備份要添加--redo-only參數,到最後一次增量備份去掉--redo-only參數)

*對總體的徹底備份進行恢復,回滾那些未提交的數據

恢復徹底備份(注意這裏必定要加--redo-only參數,該參數的意思是隻應用xtrabackup日誌中已提交的事務數據,不回滾還未提交的數據)

[root@MySQL-01 ~]# innobackupex --apply-log --redo-only /data/backup/full/2014-04-07_23-37-20/
xtrabackup: starting shutdown with innodb_fast_shutdown = 1
140407 23:59:43  InnoDB: Starting shutdown...
140407 23:59:43  InnoDB: Shutdown completed; log sequence number 5324784718
140407 23:59:43  innobackupex: completed OK!

將增量備份1應用到徹底備份

[root@MySQL-01 ~]# innobackupex --apply-log --redo-only /data/backup/full/2014-04-07_23-37-20/ --incremental-dir=/data/backup/incremental/2014-04-07_23-42-46/
innobackupex: Copying '/data/backup/incremental/2014-04-07_23-42-46/mysql/func.frm' to '/data/backup/full/2014-04-07_23-37-20/mysql/func.frm'
innobackupex: Copying '/data/backup/incremental/2014-04-07_23-42-46/mysql/help_relation.frm' to '/data/backup/full/2014-04-07_23-37-20/mysql/help_relation.frm'
innobackupex: Copying '/data/backup/incremental/2014-04-07_23-42-46/mysql/help_category.MYD' to '/data/backup/full/2014-04-07_23-37-20/mysql/help_category.MYD'
innobackupex: Copying '/data/backup/incremental/2014-04-07_23-42-46/mysql/ndb_binlog_index.frm' to '/data/backup/full/2014-04-07_23-37-20/mysql/ndb_binlog_index.frm'
140408 00:02:07  innobackupex: completed OK!
[root@MySQL-01 ~]# 

將增量備份2應用到徹底備份(注意恢復最後一個增量備份時須要去掉--redo-only參數,回滾xtrabackup日誌中那些還未提交的數據)

[root@MySQL-01 ~]# innobackupex --apply-log /data/backup/full/2014-04-07_23-37-20/ --incremental-dir=/data/backup/incremental/2014-04-07_23-51-15/
innobackupex: Copying '/data/backup/incremental/2014-04-07_23-51-15/mysql/help_relation.frm' to '/data/backup/full/2014-04-07_23-37-20/mysql/help_relation.frm'
innobackupex: Copying '/data/backup/incremental/2014-04-07_23-51-15/mysql/help_category.MYD' to '/data/backup/full/2014-04-07_23-37-20/mysql/help_category.MYD'
innobackupex: Copying '/data/backup/incremental/2014-04-07_23-51-15/mysql/ndb_binlog_index.frm' to '/data/backup/full/2014-04-07_23-37-20/mysql/ndb_binlog_index.frm'
140408 00:04:33  innobackupex: completed OK!
[root@MySQL-01 ~]# 

把全部合在一塊兒的徹底備份總體進行一次apply操做,回滾未提交的數據:

[root@MySQL-01 ~]# innobackupex --apply-log /data/backup/full/2014-04-07_23-37-20/
xtrabackup: starting shutdown with innodb_fast_shutdown = 1
140408  0:06:32  InnoDB: Starting shutdown...
140408  0:06:36  InnoDB: Shutdown completed; log sequence number 5324785676
140408 00:06:36  innobackupex: completed OK!

把恢復完的備份複製到數據庫目錄文件中,賦權,而後啓動mysql數據庫,檢測數據正確性

[root@MySQL-01 ~]# /etc/init.d/mysqld stop
Shutting down MySQL.                                       [  OK  ]
[root@MySQL-01 ~]# mv /data/mysql /data/mysql_bak
[root@MySQL-01 ~]# mkdir /data/mysql
[root@MySQL-01 ~]# innobackupex --defaults-file=/etc/my.cnf --copy-back --rsync /data/backup/full/2014-04-07_23-37-20/
innobackupex: Starting to copy InnoDB log files
innobackupex: in '/data/backup/full/2014-04-07_23-37-20'
innobackupex: back to original InnoDB log directory '/data/mysql'
innobackupex: Copying '/data/backup/full/2014-04-07_23-37-20/ib_logfile1' to '/data/mysql/ib_logfile1'
innobackupex: Copying '/data/backup/full/2014-04-07_23-37-20/ib_logfile0' to '/data/mysql/ib_logfile0'
innobackupex: Finished copying back files.
140408 00:12:42  innobackupex: completed OK!
[root@MySQL-01 ~]# chown -R mysql.mysql /data/mysql
[root@MySQL-01 ~]# /etc/init.d/mysqld start
Starting MySQL....                                         [  OK  ]
[root@MySQL-01 ~]# 

查看數據是否正確

mysql> select * from t1;
+------+-----------+
| id   | name      |
+------+-----------+
|    1 | yayun     |
|    2 | atlas     |
|    1 | love sql  |
|    1 | mysql dba |
+------+-----------+
4 rows in set (0.00 sec)

mysql> 

(5)克隆slave

在平常工做中,咱們有時候須要在線添加從庫,好比線上有一主一從兩個數據庫,可是因爲業務的須要,一臺從庫的讀取沒法知足如今的需求,這樣就須要咱們在線添加從庫,因爲出於安全考慮,咱們一般須要在從庫上進行在線克隆slave。

克隆slave時,經常使用參數--slave-info和--safe-slave-backup。

--slave-info會將master的binlog文件名和偏移量位置保存到xtrabackup_slave_info文件中

--safe-slave-backup會暫停slave的SQL線程直到沒有打開的臨時表的時候開始備份。備份結束後SQL線程會自動啓動,這樣操做的目的主要是確保一致性的複製狀態。

下面的例子,將介紹一主一從狀況下在線搭建新的從庫,環境以下:

master 192.168.0.10    #主庫

slave    192.168.0.20    #從庫

newslave 192.168.0.100 # 新的從庫

在上述示例中,newslave即爲要新搭建的從庫。在老的從庫上面進行備份:

[root@MySQL-02 ~]# innobackupex --user=root --password=12345 --socket=/tmp/mysqld.sock --defaults-file=/etc/my.cnf --slave-info --safe-slave-backup --no-timestamp /data/cloneslave
innobackupex: Backup created in directory '/data/cloneslave'
innobackupex: MySQL binlog position: filename 'mysql-bin.000022', position 107
innobackupex: MySQL slave binlog position: master host '192.168.0.10', filename 'mysql-bin.000006', position 732
140413 23:25:13  innobackupex: completed OK!

這裏的/data/cloneslave 目錄要不存在,若是存在是會報錯的。

查看目錄下生成的文件:

[root@MySQL-02 ~]# ll /data/cloneslave/
total 26668
-rw-r--r-- 1 root root      261 Apr 13 23:24 backup-my.cnf
-rw-r--r-- 1 root root 27262976 Apr 13 23:24 ibdata1
drwxr-xr-x 2 root root     4096 Apr 13 23:25 mysql
drwxr-xr-x 2 root root     4096 Apr 13 23:25 performance_schema
drwxr-xr-x 2 root root     4096 Apr 13 23:25 sakila
drwxr-xr-x 2 root root     4096 Apr 13 23:25 world_innodb
-rw-r--r-- 1 root root       13 Apr 13 23:25 xtrabackup_binary
-rw-r--r-- 1 root root       23 Apr 13 23:25 xtrabackup_binlog_info
-rw-r--r-- 1 root root       79 Apr 13 23:25 xtrabackup_checkpoints
-rw-r--r-- 1 root root     2560 Apr 13 23:25 xtrabackup_logfile
-rw-r--r-- 1 root root       72 Apr 13 23:25 xtrabackup_slave_info
drwxr-xr-x 2 root root     4096 Apr 13 23:25 yayun
[root@MySQL-02 ~]# 

查看xtrabackup_slave_info文件內容,這個內容就是爲搭建從庫時須要change master to的參數:

[root@MySQL-02 ~]# cat /data/cloneslave/xtrabackup_slave_info 
CHANGE MASTER TO MASTER_LOG_FILE='mysql-bin.000006', MASTER_LOG_POS=732
[root@MySQL-02 ~]# 

在老的slave服務器上進行還原,即192.168.0.20

[root@MySQL-02 ~]# innobackupex --apply-log --redo-only /data/cloneslave/
xtrabackup: starting shutdown with innodb_fast_shutdown = 1
140413 23:30:37  InnoDB: Starting shutdown...
140413 23:30:37  InnoDB: Shutdown completed; log sequence number 12981048
140413 23:30:37  innobackupex: completed OK!
[root@MySQL-02 ~]# 

將還原的文件複製到新的從庫newslave,即192.168.0.100

[root@MySQL-02 data]# rsync -avprP -e ssh /data/cloneslave/ 192.168.0.100:/data/mysql/

在主庫master上添加對新從庫newslave的受權:

mysql> grant replication slave on *.* to 'repl'@'192.168.0.100' identified by '123456';
Query OK, 0 rows affected (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.02 sec)

mysql> 

拷貝老的從庫的配置文件到新的從庫newslave,而且修改server-id參數,修改完畢後,啓動新的從庫;

[root@MySQL-02 data]# scp /etc/my.cnf 192.168.0.100:/etc/
 root@192.168.0.100's password: 
 my.cnf                                                                                                             100% 4881     4.8KB/s   00:00 
[root@MySQL-02 data]# 
[root@newslave mysql]# egrep 'log-slave|^server-id|skip_slave' /etc/my.cnf 
server-id       = 3
skip_slave_start
log-slave-updates=1
[root@newslave mysql]# 
[root@newslave mysql]# chown -R mysql.mysql .
[root@newslave mysql]# /etc/init.d/mysqld restart
Shutting down MySQL.                                       [  OK  ]
Starting MySQL..                                           [  OK  ]
[root@newslave mysql]# 

查找老的從庫備份後生成的xtrabackup_slave_info文件,提取其中的master_log_file和master_log_pos信息,而後在新的從庫上進行change master to操做:

在新的從庫上進行同步:

mysql> CHANGE MASTER TO MASTER_HOST='192.168.0.10',MASTER_USER='repl', MASTER_PASSWORD='123456',MASTER_LOG_FILE='mysql-bin.000006', MASTER_LOG_POS=732;
Query OK, 0 rows affected (0.09 sec)

mysql> 

啓動io線程和sql線程,並觀察複製是否正常:

mysql> start slave;
Query OK, 0 rows affected (0.00 sec)

mysql> 
mysql> show slave  status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.0.10
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 2
              Master_Log_File: mysql-bin.000006
          Read_Master_Log_Pos: 1309
               Relay_Log_File: MySQL-02-relay-bin.000002
                Relay_Log_Pos: 830
        Relay_Master_Log_File: mysql-bin.000006
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB: 
          Replicate_Ignore_DB: 
           Replicate_Do_Table: 
       Replicate_Ignore_Table: 
      Replicate_Wild_Do_Table: yayun.%
  Replicate_Wild_Ignore_Table: 
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 1309
              Relay_Log_Space: 989
              Until_Condition: None
               Until_Log_File: 
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File: 
           Master_SSL_CA_Path: 
              Master_SSL_Cert: 
            Master_SSL_Cipher: 
               Master_SSL_Key: 
        Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 1
1 row in set (0.00 sec)

mysql> 

查看主庫,發現已經有兩個線程(Binlog Dump)

mysql> show processlist\G
*************************** 1. row ***************************
     Id: 8
   User: slave
   Host: 192.168.0.20:44251
     db: NULL
Command: Binlog Dump
   Time: 1088
  State: Master has sent all binlog to slave; waiting for binlog to be updated
   Info: NULL
*************************** 2. row ***************************
     Id: 9
   User: root
   Host: localhost
     db: yayun
Command: Query
   Time: 0
  State: NULL
   Info: show processlist
*************************** 3. row ***************************
     Id: 10
   User: repl
   Host: 192.168.0.100:45844
     db: NULL
Command: Binlog Dump
   Time: 124
  State: Master has sent all binlog to slave; waiting for binlog to be updated
   Info: NULL
3 rows in set (0.00 sec)

mysql> 

正常工做,到此在線克隆slave就結束啦。

 

參考資料:

http://www.percona.com/doc/percona-xtrabackup/2.1/

http://realtimedba.blogspot.com/2013/06/my-sqlxtra-backup.html

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