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[数据库]基于MySQL MEB的备份恢复


MEB是MySQL商业版中提供的备份工具,属于物理备份。

同XtraBackup一样,mysqlbackup的使用过程同样包含如下三个步骤:

备份(--backup)=> 应用日志(--apply-log)=> 恢复(--copy-back)

 

备份

# ./mysqlbackup --backup_dir=/backup --socket=/usr/local/mysql-advanced-5.6.23-linux-glibc2.5-x86_64/data/mysql.sock backup

在备份目录下,会生成以下文件

# lsbackup-my.cnf datadir meta server-all.cnf server-my.cnf

其中datadir和meta是目录,其它是变量配置文件

backup-my.cnf

官方解释如下:

Records the configuration parameters that specify the layout of the MySQL data files.

# cat backup-my.cnf ## Generated backup-my.cnf file.# Auto generated by mysqlbackup program.#[mysqld]innodb_data_file_path=ibdata1:12M:autoextendinnodb_log_file_size=50331648innodb_log_files_in_group=2innodb_page_size=16384innodb_checksum_algorithm=innodb

server-all.cnf

该文件记录了备份数据库的所有全局参数

server-my.cnf

该文件记录了备份数据库的非默认的全局参数

注意:在恢复数据库时,可使用server-all.cnf和server-my.cnf中的任意一个。如果需要将数据库恢复到非默认路径,还要修改路径相关的变量值。

 

再来看看meta目录中的文件

# ls meta/backup_content.-09-27.10-49-21_backup.log

MEB_2016-09-27.10-49-21_backup.log

记录了此次备份的详细信息

backup_content.

记录了备份文件的元数据信息和数据库定义信息,同时还记录了备份数据库的plugin信息,恢复时必须确保这些插件在目标数据库中同样存在。

backup_create.

记录了备份操作的相关信息,包括备份命令,备份的时间,备份的目录,数据库的参数信息

上述两个文件可通过--disable-manifest选项禁用。

backup_gtid_executed.sql

因为备份数据库启动了GTID复制,故会生成该文件记录GTID的信息

# cat backup_gtid_executed.sql # On a new slave, issue the following command if GTIDs are enabled: SET @@GLOBAL.GTID_PURGED='844e8202-8391-11e6-accb-000c29c64704:1-328944';# Use the following command if you want to use the GTID handshake protocol:# CHANGE MASTER TO MASTER_AUTO_POSITION=1; 

backup_variables.txt

记录了备份的相关信息,该文件由mysqlbackup来控制的,譬如apply_log_done指示是否进行了apply-log操作

# cat backup_variables.txt ## This file is auto generated by mysqlbackup.#[backup_variables]start_lsn=98224128end_lsn=98227650apply_log_done=0is_incremental=0is_incremental_with_redo_log_only=0is_partial=0is_compressed=0is_skip_unused_pages=0binlog_position=mysql-bin.000005:65395090gtid_executed=844e8202-8391-11e6-accb-000c29c64704:1-328944is_onlyinnodb=0

关于各文件的说明,可参考官方文档的解释

https://dev.mysql.com/doc/mysql-enterprise-backup/3.12/en/meb-files-overview.html

 

应用日志

./mysqlbackup --backup-dir=/backup/ apply-log

MySQL Enterprise Backup version 3.9.0 [2013/08/23] Copyright (c) 2003, 2013, Oracle and/or its affiliates. All Rights Reserved. mysqlbackup: INFO: Starting with following command line ... ./mysqlbackup --backup-dir=/backup/ apply-log IMPORTANT: Please check that mysqlbackup run completes successfully.      At the end of a successful 'apply-log' run mysqlbackup      prints "mysqlbackup completed OK!".160927 11:38:43 mysqlbackup: INFO: MEB logfile created at /backup/meta/MEB_2016-09-27.11-38-43_apply_log.log--------------------------------------------------------------------            Backup Config Options:-------------------------------------------------------------------- datadir = /backup/datadir innodb_data_home_dir = /backup/datadir innodb_data_file_path = ibdata1:12M:autoextend innodb_log_group_home_dir = /backup/datadir innodb_log_files_in_group = 2 innodb_log_file_size = 50331648 innodb_page_size = 16384 innodb_checksum_algorithm = innodb mysqlbackup: INFO: Uses posix_fadvise() for performance optimization. mysqlbackup: INFO: Creating 14 buffers each of size 65536.160927 11:38:43 mysqlbackup: INFO: Apply-log operation starts with following threads    1 read-threads  1 process-threads160927 11:38:43 mysqlbackup: INFO: ibbackup_logfile's creation parameters:     start lsn 98224128, end lsn 98227650,     start checkpoint 98224335.InnoDB: Doing recovery: scanned up to log sequence number 98227650 mysqlbackup: INFO: InnoDB: Starting an apply batch of log records to the database...InnoDB: Progress in percent: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 mysqlbackup: INFO: InnoDB: Setting log file size to 50331648 mysqlbackup: INFO: InnoDB: Setting log file size to 50331648160927 11:38:48 mysqlbackup: INFO: We were able to parse ibbackup_logfile up to     lsn 98227650. mysqlbackup: INFO: Last MySQL binlog file position 0 65394957, file name mysql-bin.000005160927 11:38:48 mysqlbackup: INFO: The first data file is '/backup/datadir/ibdata1'     and the new created log files are at '/backup/datadir'160927 11:38:48 mysqlbackup: INFO: Apply-log operation completed successfully.160927 11:38:48 mysqlbackup: INFO: Full backup prepared for recovery successfully.mysqlbackup completed OK!

在应用日志之前,

数据目录中并没有redo log

[root@localhost datadir]# lsibbackup_logfile ibdata1 mysql performance_schema test

在应用完日志之后,

数据目录中会生成redo log

[root@localhost datadir]# lsibbackup_logfile ibdata1 ib_logfile0 ib_logfile1 mysql performance_schema test

 

恢复

./mysqlbackup --defaults-file=/backup/server-my.cnf --backup-dir=/backup/ copy-back

./mysqlbackup --defaults-file=/backup/server-my.cnf --backup-dir=/backup/ copy-backMySQL Enterprise Backup version 3.9.0 [2013/08/23] Copyright (c) 2003, 2013, Oracle and/or its affiliates. All Rights Reserved. mysqlbackup: INFO: Starting with following command line ... ./mysqlbackup --defaults-file=/backup/server-my.cnf     --backup-dir=/backup/ copy-back IMPORTANT: Please check that mysqlbackup run completes successfully.      At the end of a successful 'copy-back' run mysqlbackup      prints "mysqlbackup completed OK!".160927 15:26:55 mysqlbackup: INFO: MEB logfile created at /backup/meta/MEB_2016-09-27.15-26-55_copy_back.log--------------------------------------------------------------------            Server Repository Options:-------------------------------------------------------------------- datadir = /usr/local/mysql-advanced-5.6.23-linux-glibc2.5-x86_64/data/ innodb_data_home_dir = /usr/local/mysql-advanced-5.6.23-linux-glibc2.5-x86_64/data/ innodb_data_file_path = ibdata1:12M:autoextend innodb_log_group_home_dir = /usr/local/mysql-advanced-5.6.23-linux-glibc2.5-x86_64/data/ innodb_log_files_in_group = 2 innodb_log_file_size = 50331648 innodb_page_size = 16384 innodb_checksum_algorithm = innodb innodb_undo_directory = /usr/local/mysql-advanced-5.6.23-linux-glibc2.5-x86_64/data/ innodb_undo_tablespaces = 0 innodb_undo_logs = 128--------------------------------------------------------------------            Backup Config Options:-------------------------------------------------------------------- datadir = /backup/datadir innodb_data_home_dir = /backup/datadir innodb_data_file_path = ibdata1:12M:autoextend innodb_log_group_home_dir = /backup/datadir innodb_log_files_in_group = 2 innodb_log_file_size = 50331648 innodb_page_size = 16384 innodb_checksum_algorithm = innodb mysqlbackup: INFO: Uses posix_fadvise() for performance optimization. mysqlbackup: INFO: Creating 14 buffers each of size 16777216.160927 15:26:55 mysqlbackup: INFO: Copy-back operation starts with following threads    1 read-threads  1 write-threads160927 15:26:55 mysqlbackup: INFO: Copying /backup/datadir/ibdata1 (to '/usr/local/mysql-advanced-5.6.23-linux-glibc2.5-x86_64/data').160927 15:26:59 mysqlbackup: INFO: Copying /backup/datadir/mysql/innodb_index_stats.ibd.160927 15:26:59 mysqlbackup: INFO: Copying /backup/datadir/mysql/innodb_table_stats.ibd.160927 15:26:59 mysqlbackup: INFO: Copying /backup/datadir/mysql/slave_master_info.ibd.160927 15:26:59 mysqlbackup: INFO: Copying /backup/datadir/mysql/slave_relay_log_info.ibd.160927 15:26:59 mysqlbackup: INFO: Copying /backup/datadir/mysql/slave_worker_info.ibd.160927 15:27:00 mysqlbackup: INFO: Copying /backup/datadir/test/test.ibd.160927 15:27:00 mysqlbackup: INFO: Copying the database directory 'mysql'160927 15:27:00 mysqlbackup: INFO: Copying the database directory 'performance_schema'160927 15:27:00 mysqlbackup: INFO: Copying the database directory 'test'160927 15:27:00 mysqlbackup: INFO: Completing the copy of all non-innodb files.160927 15:27:00 mysqlbackup: INFO: Copying the log file 'ib_logfile0'160927 15:27:04 mysqlbackup: INFO: Copying the log file 'ib_logfile1'160927 15:27:07 mysqlbackup: INFO: Creating server config files server-my.cnf and server-all.cnf in /usr/local/mysql-advanced-5.6.23-linux-glibc2.5-x86_64/data/160927 15:27:07 mysqlbackup: INFO: Copy-back operation completed successfully.160927 15:27:07 mysqlbackup: INFO: Finished copying backup files to '/usr/local/mysql-advanced-5.6.23-linux-glibc2.5-x86_64/data/'mysqlbackup completed OK!

关于恢复,有以下几点需要注意

1. 恢复必须使用配置文件,建议备份目录下的server-all.cnf和server-my.cnf,事实上,在恢复的过程中,mysqlbackup需要明确上述输出中的参数,譬如,我使用了自己的配置文件进行恢复,结果报如下错误:

# ./mysqlbackup --defaults-file=/usr/local/mysql-advanced-5.6.23-linux-glibc2.5-x86_64/my.cnf --backup-dir=/backup/ copy-backMySQL Enterprise Backup version 3.9.0 [2013/08/23] Copyright (c) 2003, 2013, Oracle and/or its affiliates. All Rights Reserved. mysqlbackup: INFO: Starting with following command line ... ./mysqlbackup     --defaults-file=/usr/local/mysql-advanced-5.6.23-linux-glibc2.5-x86_64/my.cnf     --backup-dir=/backup/ copy-back IMPORTANT: Please check that mysqlbackup run completes successfully.      At the end of a successful 'copy-back' run mysqlbackup      prints "mysqlbackup completed OK!".160927 15:26:09 mysqlbackup: INFO: MEB logfile created at /backup/meta/MEB_2016-09-27.15-26-09_copy_back.log mysqlbackup: ERROR: Server innodb_log_files_in_group is missing or invalid mysqlbackup: ERROR: Server repository configuration problem found.mysqlbackup failed with errors!

很显然,我的配置文件中并没有定义innodb_log_files_in_group参数。

2. 可在上述配置文件中server-all.cnf和server-my.cnf自定义数据目录和base目录,不然默认的都是备份数据库的。

3. 虽然mysqlbackup --help中的解释是:The restore operation assumes the server is offline. Use of this command when server is running is not supported.

   但事实上,在server是online的情况下,执行恢复操作并没有报错,甚至还显示“mysqlbackup completed OK!”。但是,并没有覆盖数据目录中的文件。

4. 在启动数据库的过程中,可以使用server-my.cnf或备份数据库的配置文件,不要使用server-all.cnf。在使用server-all.cnf启动数据库的过程中,会报如下错误:

2016-09-27 15:51:37 85229 [ERROR] /usr/local/mysql-advanced-5.6.23-linux-glibc2.5-x86_64/bin/mysqld: Table './mysql/user' is marked as crashed and should be repaired2016-09-27 15:51:37 85229 [ERROR] Fatal error: Can't open and lock privilege tables: Table './mysql/user' is marked as crashed and should be repaired

   这个坑定位了好久,因为server-all.cnf中定义的是所有参数的配置,怀疑跟某些参数有关,因参数较多,时间有限,并没有一一验证。

 

启动数据库

修改数据目录的权限

# chown -R mysql.mysql /usr/local/mysql-advanced-5.6.23-linux-glibc2.5-x86_64/data

启动数据库

# /usr/local/mysql-advanced-5.6.23-linux-glibc2.5-x86_64/bin/mysqld --defaults-file=/usr/local/mysql-advanced-5.
6.23-linux-glibc2.5-x86_64/my.cnf --user=mysql &

 

总结

以上只是mysqlbackup的一个简单的备份恢复流程,事实上,mysqlbackup还支持压缩备份等高级特性,后续再表。