MySQL 5.6表空间传输

在MySQL 5.6 Oracle引入了一个可移动表空间的特征（复制的表空间到另一个服务器）和Percona Server采用部分备份，这意味着你现在可以备份单个数据库或表；由于Percona Server 5.6的出现，innodb_import_table_from_xtrabackup是过时的Percona Server实现Oracle MySQL的可移动表空间的功能，就是在服务器之间复制的表空间的能力（table.ibd）。让我展示通过一个例子，我将采取选择性表部分备份而不是一个完整的MySQL服务器并且在线恢复它，而不需要关闭MySQL服务器

该实验用到一个备份工具percona xtrabackup，是一个开源且免费的MySQL数据库热备份软件,执行非阻塞InnoDB和xtradb数据库备份，想当好用， 最重要Percona支持部分备份模式，对应于特定的数据库或表格备份。

本实验环境：

服务器端版本：percona-5.6.21版本（下载地址：http://www.percona.com/downloads/Percona-Server-5.6/Percona-Server-5.6.21-70.1/binary/tarball/Percona-Server-5.6.21-rel70.1-698.Linux.x86_64.tar.gz）

附加：percona-5.5.40版本 (下载地址：http://www.percona.com/downloads/Percona-Server-5.5/Percona-Server-5.5.40-36.1/binary/tarball/Percona-Server-5.5.40-rel36.1-707.Linux.x86_64.tar.gz)

备份工具版本：percona-xtrabackup-2.2.5（下载地址：http://www.percona.com/downloads/XtraBackup/XtraBackup-2.2.5/binary/tarball/percona-xtrabackup-2.2.5-5027-Linux-x86_64.tar.gz）

安装过程非常简单，这里不作说明

方法一：

一、检查是否开启了独立表空间

mysql> show global variables like '%innodb_file_pe%';
+-----------------------+-------+
| Variable_name         | Value |
+-----------------------+-------+
| innodb_file_per_table | ON    |
+-----------------------+-------+
1 row in set (0.00 sec)

二、创建一个库，在库里创建一个test表，插入点数据，一会好验证。在实验中，我发现（虽然MySQL5.6版本默认已经开启innodb_file_per_table选项，但在percona5.6的版本，我查看的时候是ON状态，但创建表的时候，只生成.frm文件而没有.ibd文件，所以创建表时，要查看下是否成功开启独立表空间了）：

mysql> create database irfan;
Query OK, 1 row affected (0.07 sec)
 
mysql> use irfan;
Database changed
mysql> CREATE TABLE `test` (
    ->   `id` int(11) DEFAULT NULL,
    ->   `name` char(15) DEFAULT NULL
    -> ) ENGINE=InnoDB DEFAULT CHARSET=latin1;
Query OK, 0 rows affected (0.11 sec)
 
mysql> insert into test select * from testdb.test;
Query OK, 10 rows affected (0.05 sec)
Records: 10  Duplicates: 0  Warnings: 0
 
mysql> select * from test;
+------+------+
| id   | name |
+------+------+
|    1 | aa   |
|    2 | bb   |
|    3 | cc   |
|    4 | dd   |
|    5 | ee   |
|    6 | ff   |
|    7 | gg   |
|    8 | hh   |
|    9 | ii   |
|   10 | jj   |
+------+------+
10 rows in set (0.00 sec)
 
mysql> system ls -l /data/percona5.6/irfan/ 
总用量 112
-rw-rw---- 1 percona5.6 percona5.6    65 12月  5 21:36 db.opt
-rw-rw---- 1 percona5.6 percona5.6  8586 12月  5 21:37 test.frm
-rw-rw---- 1 percona5.6 percona5.6 98304 12月  5 21:38 test.ibd

三、把table_schema为irfan（就是刚刚创建的库）下的表test导出，保存为.txt的格式

[root ~]$ /usr/local/percona-5.6/bin/mysql -uroot -p123456 -S /data/percona5./mysql.sock --skip-column-names \
> -e "SELECT CONCAT(table_schema,'.',table_name) FROM   information_schema.tables tables \
> WHERE table_schema IN ('irfan') AND TABLE_NAME = 'test';" > /root/tables_to_backup.txt
[root ~]$ cat  /root/tables_to_backup.txt
irfan.test

四、我们用比较新版本的Percona xtrabackup，因为支持多种方式采取部分备份，我们用--tables-file选项备份特定的表。( /root/partial_backup/ 这目录不用创建，如果之前存在，会报错innobackupex: Error: Failed to create backup directory /root/partial_backup/: 文件已存在 at /usr/bin/innobackupex line 3949.)

[root ~]$ xtrabackup --version
xtrabackup version 2.2. based on MySQL server 5.6. Linux (x86_64) (revision id: )
[root ~]$ innobackupex --defaults-file=/usr/local/percona-5.6/my.cnf --user=root --password= --port= --sock=/data/percona5./mysql.sock \
> --no-timestamp --tables-file=/root/tables_to_backup.txt /root/partial_backup/ > /root/xtrabackup.log >&
[root irfan]$ pwd
/root/partial_backup/irfan
[root irfan]$ ls
test.frm  test.ibd

查看一下备份成功了没，若completed OK，那就OK了：

[root ~]$ cat xtrabackup.log
...
.........
innobackupex: Backup created in directory '/root/partial_backup'
innobackupex: MySQL binlog position: filename 'mysql-bin.000003', position , GTID of the last change ''
 ::  innobackupex: Connection to database server closed
 ::  innobackupex: completed OK!

下一步，我们需要准备备份，因为可能会有uncomitted事务需要回滚或事务日志重播备份， --export选项是为了创建 table.exp and table.cfg

[root ~]$ innobackupex --defaults-file=/usr/local/percona-5.6/my.cnf --user=root --password= --port= --sock=/data/percona5./mysql.sock \
> -apply-log --export /root/partial_backup/ > /root/xtrabackup-prepare.log >&
[root irfan]$ pwd
/root/partial_backup/irfan
[root irfan]$ ls
test.cfg  test.exp  test.frm  test.ibd

查看日志最后是否为completed OK

[root ~]$ cat xtrabackup-prepare.log
...
........
xtrabackup: starting shutdown with innodb_fast_shutdown =
InnoDB: FTS optimize thread exiting.
InnoDB: Starting shutdown...
InnoDB: Shutdown completed; log sequence number
 ::  innobackupex: completed OK!

五、（在还原机上操作）在另一台服务器进行还原操作：（我用的是percona5.6的沙箱环境，有关沙箱的安装，请查看我的博客：http://www.cnblogs.com/xuanzhi201111/p/3998604.html）

同样要确定独立表空间已经开启了，然后创建表，表结构要和原来备份的一致：

mysql [localhost] {msandbox} (none) > show variables like 'innodb_file_per_table';
+-----------------------+-------+
| Variable_name         | Value |
+-----------------------+-------+
| innodb_file_per_table | ON    |
+-----------------------+-------+
1 row in set (0.00 sec)
mysql [localhost] {msandbox} ((none)) > create database irfan;
Query OK, 1 row affected (0.02 sec)
mysql [localhost] {msandbox} ((none)) > use irfan;
Database changed
mysql [localhost] {msandbox} (irfan) > CREATE TABLE `test` ( `id` int(11) DEFAULT NULL, `name` char(15) DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=latin1;
Query OK, 0 rows affected (0.12 sec)

执行丢弃表空间命令

mysql [localhost] {msandbox} (irfan) > ALTER TABLE test DISCARD TABLESPACE;
Query OK, 0 rows affected (0.02 sec)

查看发现.ibd表空间文件没了：

[root irfan]$ ls
db.opt  test.frm

（在目标机操作）在备份的服务器上，把备份的表空间文件scp过来，注意：（要查看test.cfg文件和test.ibd文件权限是否给对）

[root irfan]$ pwd
/root/partial_backup/irfan
[root irfan]$ scp  test.cfg test.ibd
192.168.1.128:/root/sandboxes/msb_5_6_21/data/irfan

（在还原机操作）执行导入表空间命令，然后查看表数据：

mysql [localhost] {msandbox} (irfan) > ALTER TABLE test IMPORT TABLESPACE;
Query OK, 0 rows affected (0.04 sec)
 
mysql [localhost] {msandbox} (irfan) > select * from test;
+------+------+
| id   | name |
+------+------+
|    1 | aa   |
|    2 | bb   |
|    3 | cc   |
|    4 | dd   |
|    5 | ee   |
|    6 | ff   |
|    7 | gg   |
|    8 | hh   |
|    9 | ii   |
|   10 | jj   |
+------+------+
10 rows in set (0.00 sec)

（还原机查看）数据已经导回来，但为了安全起见，最好看看错误日志是否有报错，正常的应该没warning和error字眼的：

[root data]$ tail -f msandbox.err
2014-12-11 16:16:27 34035 [Note] InnoDB: Waiting for purge to start
2014-12-11 16:16:27 34035 [Note] InnoDB:  Percona XtraDB (http://www.percona.com) 5.6.21-rel70.1 started; log sequence number 1752156
2014-12-11 16:16:27 34035 [Note] RSA private key file not found: /root/sandboxes/msb_5_6_21/data//private_key.pem. Some authentication plugins will not work.
2014-12-11 16:16:27 34035 [Note] RSA public key file not found: /root/sandboxes/msb_5_6_21/data//public_key.pem. Some authentication plugins will not work.
2014-12-11 16:16:27 34035 [Note] Server hostname (bind-address): '127.0.0.1'; port: 5621
2014-12-11 16:16:27 34035 [Note]   - '127.0.0.1' resolves to '127.0.0.1';
2014-12-11 16:16:27 34035 [Note] Server socket created on IP: '127.0.0.1'.
2014-12-11 16:16:27 34035 [Note] Event Scheduler: Loaded 0 events
2014-12-11 16:16:27 34035 [Note] /usr/local/src/5.6.21/bin/mysqld: ready for connections.
Version: '5.6.21-70.1'  socket: '/tmp/mysql_sandbox5621.sock'  port: 5621  Percona Server (GPL), Release 70.1, Revision 698
2014-12-11 16:19:05 34035 [Note] InnoDB: Importing tablespace for table 'irfan/test' that was exported from host 'Hostname unknown'
2014-12-11 16:19:05 34035 [Note] InnoDB: Phase I - Update all pages
2014-12-11 16:19:05 34035 [Note] InnoDB: Sync to disk
2014-12-11 16:19:05 34035 [Note] InnoDB: Sync to disk - done!
2014-12-11 16:19:05 34035 [Note] InnoDB: Phase III - Flush changes to disk
2014-12-11 16:19:05 34035 [Note] InnoDB: Phase IV - Flush complete

哈哈，已经成功还原表数据了^.^

方法二：从运行MySQL实例复制表到另一个运行MySQL服务器是在MySQL手册描述了另一种方法:

mysql> show create table dummy;
+-------+-------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                                                  |
+-------+-------------------------------------------------------------------------------------------------------------------------------+
| dummy | CREATE TABLE `dummy` (
  `id` int(11) DEFAULT NULL,
  `dummy` varchar(10) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+-------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
 
mysql> select * from dummy;
+------+-------+
| id   | dummy |
+------+-------+
|    1 | aa    |
|    2 | bb    |
|    3 | cc    |
|    4 | dd    |
|    5 | ee    |
|    6 | ff    |
|    7 | gg    |
|    8 | hh    |
|    9 | ii    |
|   10 | jj    |
+------+-------+
10 rows in set (0.00 sec)
 
mysql> 

FLUSH TABLES FOR EXPORT只适用于Oracle MySQL 5.6/Percona Server 5.6，FLUSH TABLES FOR EXPORT会产生表的元数据文件（.cfg)和表空间文件(.ibd)

mysql> FLUSH TABLES dummy FOR EXPORT;
Query OK, 0 rows affected (0.00 sec)
mysql> 

进到数据目录下查看已经产生了dummy.cfg和dummy.idb文件了：

[root irfan]$ pwd
/data/percona5./irfan
[root irfan]$ ls
db.opt  dummy.cfg  dummy.frm  dummy.ibd  test.frm  test.ibd

去到另一台服务器，创建表，表结构一定要和目标MySQL上的一样，再执行丢弃表空间命令：

mysql [localhost] {msandbox} (irfan) > use irfan;
Database changed
mysql [localhost] {msandbox} (irfan) > CREATE TABLE `dummy` ( `id` int(11) DEFAULT NULL, `dummy` varchar(10) DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=latin1;
Query OK, 0 rows affected (0.04 sec)
 
mysql [localhost] {msandbox} (irfan) >  ALTER TABLE dummy DISCARD TABLESPACE;
Query OK, 0 rows affected (0.03 sec)

回到目标服务器,把dummy.cfg和dummy.ibd远程拷备到另一台服务器上：

[root irfan]$ scp  dummy.cfg  dummy.ibd 192.168.1.128:/root/sandboxes/msb_5_6_21/data/irfan

然后回到数据库执行解释操作，再查看，已经没有dummy.cfg文件了,所以一定确定scp完了后再解锁：

mysql> UNLOCK TABLES;
Query OK,  rows affected (0.06 sec)
 
[root irfan]$ ls
db.opt  dummy.frm  dummy.ibd  test.frm  test.ibd

执行导入表空间命令，然后查看表数据：

mysql [localhost] {msandbox} (irfan) >  ALTER TABLE dummy IMPORT TABLESPACE;
Query OK,  rows affected (0.03 sec)
 
mysql [localhost] {msandbox} (irfan) > show tables;
+-----------------+
| Tables_in_irfan |
+-----------------+
| dummy           |
| test            |
+-----------------+
 rows in set (0.00 sec)
 
mysql [localhost] {msandbox} (irfan) > select * from dummy;
+------+-------+
| id   | dummy |
+------+-------+
|     | aa    |
|     | bb    |
|     | cc    |
|     | dd    |
|     | ee    |
|     | ff    |
|     | gg    |
|     | hh    |
|     | ii    |
|    | jj    |
+------+-------+
 rows in set (0.00 sec)

查看日志，已经成功导入了^。^

-- ::  [Note] InnoDB: Importing tablespace for table 'irfan/dummy' that was exported from host 'Hostname unknown'
-- ::  [Note] InnoDB: Phase I - Update all pages
-- ::  [Note] InnoDB: Sync to disk
-- ::  [Note] InnoDB: Sync to disk - done!
-- ::  [Note] InnoDB: Phase III - Flush changes to disk
-- ::  [Note] InnoDB: Phase IV - Flush complete

总结：第一种方法步骤多一些，而且要借用开源的备份工具percona-xtrabackup，而且要是版本比较新的;

        第二种方法，步骤简单，操作起来方便，但是要进行锁表操作，而且FLUSH TABLES FOR EXPORT只适用于Oracle MySQL 5.6/Percona Server 5.6，对于一个繁忙的OLTP系统，如果表比较大，锁住的时间比较长，对业务影响比较大

参考资料：http://www.percona.com/blog/2014/12/09/mysql-5-6-transportable-tablespaces-best-practices/

作者：陆炫志

出处：xuanzhi的博客 http://www.cnblogs.com/xuanzhi201111

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