【環境介紹】
系統環境：CentOS release 6.4 (Final) + Server version: 5.7.18-log MySQL Community Server (GPL) + innobackupex version 2.4.12 Linux (x86_64)
【背景描述】
使用innobackupex重新全備搭建主從復制步驟簡單，但是由於歷史原因在全備恢復后出現報錯：。
[ERROR] InnoDB: Unable to open undo tablespace './/undo001'.
[ERROR] InnoDB: Plugin initialization aborted with error Generic error
[ERROR] Plugin 'InnoDB' init function returned error.
[ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
【實施步驟】
主庫操作：
主庫備份全庫
innobackupex --defaults-file=/etc/my.cnf --user=root --password=mysql -S /tmp/mysql.sock /root/backup
xtrabackup: recognized server arguments: --datadir=/var/lib/mysql/data --server-id=101 --open_files_limit=65535 --tmpdir=/home/mysql/tmp --innodb_buffer_pool_size=1G --innodb_flush_log_at_trx_commit=1 --innodb_undo_tablespaces=3 -
181222 04:40:18 completed OK!
[root@mysqldb2 backup]#
將備份文件拷貝至備庫
2018-12-22_04-39-56/
....》》省略部分
2018-12-22_04-39-56/sys/x@0024user_summary_by_statement_type.frm
[root@mysqldb2 backup]#
root@192.168.8.100's password:
2018-12-22_04-39-56.tar 100% 299MB 37.4MB/s 00:08
[root@mysqldb2 backup]#
備庫操作：
關閉數據庫
[root@mysqldb1 mysql]# mysqladmin --defaults-file=/etc/my.cnf --protocol=tcp -P3306 shutdown -uroot -pmysql
[root@mysqldb1 mysql]#
[1]+ Done mysqld --defaults-file=/etc/my.cnf --user=mysql (wd: ~)
(wd now: /var/lib/mysql)
[root@mysqldb1 mysql]#
備份原庫數據
[root@mysqldb1 mysql]# ls -trl
total 56
drwxr-xr-x. 6 mysql mysql 4096 Dec 22 08:47 data
[root@mysqldb1 mysql]# mv data data_bak
進行全庫恢復
進行--apply-log操作
xtrabackup: recognized server arguments: --innodb_checksum_algorithm=crc32 --innodb_log_checksum_algorithm=strict_crc32 --innodb_data_file_path=ibdata1:256M:autoextend --innodb_log_files_in_group=2 --
181222 08:52:03 completed OK!
[root@mysqldb1 mysql]#
進行--copy-back操作
[root@mysqldb1 mysql]# innobackupex --defaults-file=/etc/my.cnf --copy-back /root/backup/2018-12-22_04-39-56
xtrabackup: recognized server arguments: --datadir=/var/lib/mysql/data --server-id=100 --open_files_limit=65535 --tmpdir=/home/mysql/tmp --innodb_buffer_pool_size=1G --innodb_flush_log_at_trx_commit=1 --innodb_log_buffer_size=32M -
....》》省略部分
181222 08:53:24 [01] ...done
181222 08:53:24 completed OK!
[root@mysqldb1 mysql]#
修改數據文件目錄權限
[root@mysqldb1 mysql]# chown -R mysql:mysql data
直接啟動數據庫
[root@mysqldb1 mysql]#mysqld --defaults-file=/etc/my.cnf --user=mysql &
查看日志出現報錯：
2018-12-22T13:56:09.138266Z 0 [Warning] option 'max_binlog_size': unsigned value 2147483648 adjusted to 1073741824
2018-12-22T13:56:09.138392Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2018-12-22T13:56:09.138450Z 0 [Warning] Insecure configuration for --secure-file-priv: Current value does not restrict location of generated files. Consider setting it to a valid, non-empty path.
2018-12-22T13:56:09.138502Z 0 [Note] mysqld (mysqld 5.7.18-log) starting as process 4873 ...
2018-12-22T13:56:09.197459Z 0 [Note] InnoDB: PUNCH HOLE support not available
2018-12-22T13:56:09.197501Z 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2018-12-22T13:56:09.197513Z 0 [Note] InnoDB: Uses event mutexes
2018-12-22T13:56:09.197525Z 0 [Note] InnoDB: GCC builtin __sync_synchronize() is used for memory barrier
2018-12-22T13:56:09.197536Z 0 [Note] InnoDB: Compressed tables use zlib 1.2.3
2018-12-22T13:56:09.197547Z 0 [Note] InnoDB: Using Linux native AIO
2018-12-22T13:56:09.198473Z 0 [Note] InnoDB: Number of pools: 1
2018-12-22T13:56:09.198675Z 0 [Note] InnoDB: Using CPU crc32 instructions
2018-12-22T13:56:09.200901Z 0 [Note] InnoDB: Initializing buffer pool, total size = 1G, instances = 1, chunk size = 128M
2018-12-22T13:56:09.400867Z 0 [Note] InnoDB: Completed initialization of buffer pool
2018-12-22T13:56:09.408553Z 0 [Note] InnoDB: If the mysqld execution user is authorized, page cleaner thread priority can be changed. See the man page of setpriority().
2018-12-22T13:56:09.494523Z 0 [ERROR] InnoDB: Unable to open undo tablespace './/undo001'.
2018-12-22T13:56:09.494551Z 0 [ERROR] InnoDB: Plugin initialization aborted with error Generic error
2018-12-22T13:56:10.101405Z 0 [ERROR] Plugin 'InnoDB' init function returned error.
2018-12-22T13:56:10.101433Z 0 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2018-12-22T13:56:10.101443Z 0 [ERROR] Failed to initialize plugins.
2018-12-22T13:56:10.101451Z 0 [ERROR] Aborting
2018-12-22T13:56:10.101521Z 0 [Note] Shutting down plugin 'CSV'
2018-12-22T13:56:10.102134Z 0 [Note] mysqld: Shutdown complete
【問題解決】
從以上報錯發現無法打開undo tablespace undo001，查看備庫數據目錄查看，確實不存在undo001，查看主庫存在undo001表空間。
從恢復日志看--apply-log的時候石有undo表空間的信息
InnoDB: Opened 3 undo tablespaces
InnoDB: 3 undo tablespaces made active
從恢復日志看--copy-back的時候並沒有拷貝undo表空間的信息。思考為啥沒有copy的undo表空間到數據目錄信息
innobackupex --defaults-file=/etc/my.cnf --apply-log /root/backup/2018-12-22_04-39-56
根據思路從命令恢復的可以看出涉及兩個文件確認undo表空間信息/etc/my.cnf，/root/backup/2018-12-22_04-39-56
[root@mysqldb1 ~]# cat /etc/my.cnf |grep undo
[root@mysqldb1 ~]# ls -trl /root/backup/2018-12-22_04-39-56|grep undo
-rw-r-----. 1 root root 10485760 Dec 22 08:51 undo003
-rw-r-----. 1 root root 10485760 Dec 22 08:51 undo002
-rw-r-----. 1 root root 10485760 Dec 22 08:51 undo001
[root@mysqldb1 ~]#
從上面的結果可以看出備份文件中是存在undo表空間且是3個undo表空間，但是從參數文件中不存在undo表空間的信息
至此可以初步斷定為參數文件中沒有指定undo表空間信息，於是在配置文件中添加innodb_undo_tablespaces=3，再次--apply-log操作
觀察日志信息，已經存在undo拷貝操作
innobackupex version 2.4.12 based on MySQL server 5.7.19 Linux (x86_64) (revision id: 170eb8c)
181223 03:09:12 [01] Copying undo001 to /var/lib/mysql/data/undo001
181223 03:09:12 [01] ...done
181223 03:09:12 [01] Copying undo002 to /var/lib/mysql/data/undo002
181223 03:09:13 [01] ...done
181223 03:09:13 [01] Copying undo003 to /var/lib/mysql/data/undo003
181223 03:09:13 [01] ...done
181223 03:09:14 [01] Copying ib_logfile0 to /var/lib/mysql/data/ib_logfile0
181223 03:09:15 [01] ...done
181223 03:09:15 [01] Copying ib_logfile1 to /var/lib/mysql/data/ib_logfile1
於是手工再次啟動數據庫，數據庫正常拉起，沒有undo報錯，繼續搭建主從復制。
【錯誤日志warring】
2018-12-22T13:56:08.963837Z 0 [Warning] option 'table_definition_cache': unsigned value 64 adjusted to 400
2018-12-22T13:56:09.138266Z 0 [Warning] option 'max_binlog_size': unsigned value 2147483648 adjusted to 1073741824
2018-12-22T13:56:09.138392Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2018-12-22T13:56:09.138450Z 0 [Warning] Insecure configuration for --secure-file-priv: Current value does not restrict location of generated files. Consider setting it to a valid, non-empty path.
根據5.7官方文檔對應參數調整如下：
table_definition_cache默認值為400，可以調整400 + (table_open_cache / 2)
max_binlog_size=1024M
explicit_defaults_for_timestamp = ON
secure_file_priv = " "
【主從復制搭建】
[root@mysqldb1 2018-12-22_04-39-56]# cat xtrabackup_binlog_info
binlog.000011 489 2478c036-bd7a-11e8-85df-080027206a62:5-6,fbfd9bcb-0437-11e9-947d-080027206a62:1-9
[root@mysqldb1 2018-12-22_04-39-56]#
Query OK, 0 rows affected (0.12 sec)
Query OK, 0 rows affected (0.00 sec)
Query OK, 0 rows affected, 2 warnings (0.48 sec)
Query OK, 0 rows affected (0.04 sec)
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.8.101
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: binlog.000013
Read_Master_Log_Pos: 234
Relay_Log_File: mysqldb1-relay-bin.000002
Relay_Log_Pos: 361
Relay_Master_Log_File: binlog.000013
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Auto_Position: 1
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.00 sec)
【總結】
innobackupex備份恢復前確認主庫跟恢復庫的參數一致，可以使用diff命令查看參數的必要性；
可能由於歷史原因參數沒有寫到配置文件報錯，應該做好工程修改記錄對於問題查找有很大的作用。