MySQL中ib_logfile和ibdata1参数大小被修改后

2ewyt

1. 环境说明

RHEL 6.4 x86_64 + MySQL 5.5.37和MySQL 5.6.19



2. 案例：redo log文件（ib_logfile）大小参数被修改：innodb_log_file_size

innodb_log_file_size = 256M  -- 修改为200M

版本是5.5的，启动失败，会出现如下错误：



    InnoDB: Error: log file ./ib_logfile0 is of different size 0 268435456 bytes  ## 原来redo log的大小  
    InnoDB: than specified in the .cnf file 0 209715200 bytes!   ## redo log被修改的大小  
    140912  0:01:12 [ERROR] Plugin 'InnoDB' init function returned error.  
    140912  0:01:12 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.  
    140912  0:01:12 [ERROR] Unknown/unsupported storage engine: InnoDB  
    140912  0:01:12 [ERROR] Aborting  


版本是5.6.16之后的，正常启动，会自动将原来的redo log删除，然后重新生成新的redo log（这个比较重要）：



    2014-09-11 21:57:05 1093 [Warning] InnoDB: Resizing redo log from 2*16384 to 2*12800 pages, LSN=71249171  
    2014-09-11 21:57:05 1093 [Warning] InnoDB: Starting to delete and rewrite log files.    ## 删除原redo log  
    2014-09-11 21:57:05 1093 [Note] InnoDB: Setting log file ./ib_logfile101 size to 200 MB  
    InnoDB: Progress in MB: 100 200  
    2014-09-11 21:57:06 1093 [Note] InnoDB: Setting log file ./ib_logfile1 size to 200 MB  
    InnoDB: Progress in MB: 100 200  
    2014-09-11 21:57:07 1093 [Note] InnoDB: Renaming log file ./ib_logfile101 to ./ib_logfile0  
    2014-09-11 21:57:07 1093 [Warning] InnoDB: New log files created, LSN=71249171   ## 新redo log重建完毕  


原redo log大小：2*16384*8(page的大小为8k)/1024=256MB

新redo log大小：2*12800*8/1024=200MB


3. 案例：ibdata1文件大小参数被修改：innodb_data_file_path

（1）ibdata1从大改小

innodb_data_file_path = ibdata1:1G:autoextend  -- 修改为：ibdata1:300M:autoextend

在版本是5.5和5.6中，启动正常，并且日志中没有任何异常。但是如果将autoextend去掉，就会报错，启动失败，如：[版本：5.5.37]



    InnoDB: Error: data file ./ibdata1 is of a different size  
    InnoDB: 65536 pages (rounded down to MB)  
    InnoDB: than specified in the .cnf file 19200 pages!  
    140911 23:51:53 InnoDB: Could not open or create data files.  
    140911 23:51:53 InnoDB: If you tried to add new data files, and it failed here,  
    140911 23:51:53 InnoDB: you should now edit innodb_data_file_path in my.cnf back  
    140911 23:51:53 InnoDB: to what it was, and remove the new ibdata files InnoDB created  
    140911 23:51:53 InnoDB: in this failed attempt. InnoDB only wrote those files full of  
    140911 23:51:53 InnoDB: zeros, but did not yet use them in any way. But be careful: do not  
    140911 23:51:53 InnoDB: remove old data files which contain your precious data!  
    140911 23:51:53 [ERROR] Plugin 'InnoDB' init function returned error.  
    140911 23:51:53 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.  
    140911 23:51:53 [ERROR] Unknown/unsupported storage engine: InnoDB  
    140911 23:51:53 [ERROR] Aborting  
      
    原来的ibdata1大小为：65536*8*2/1024=1024M=1G  
    当前ibdata1被修改为：19200*8*2/1024=300M  


（2）ibdata1值小改大

比如：

innodb_data_file_path = ibdata1:1G:autoextend  -- 修改为：ibdata1:1200M:autoextend

那么会在启动时出现如下错误：

*****在5.5版本中：[版本：5.5.37]



    InnoDB: Error: auto-extending data file ./ibdata1 is of a different size  
    InnoDB: 65536 pages (rounded down to MB) than specified in the .cnf file:  
    InnoDB: initial 76800 pages, max 0 (relevant if non-zero) pages!  
    140911 23:57:43 InnoDB: Could not open or create data files.  
    140911 23:57:43 InnoDB: If you tried to add new data files, and it failed here,  
    140911 23:57:43 InnoDB: you should now edit innodb_data_file_path in my.cnf back  
    140911 23:57:43 InnoDB: to what it was, and remove the new ibdata files InnoDB created  
    140911 23:57:43 InnoDB: in this failed attempt. InnoDB only wrote those files full of  
    140911 23:57:43 InnoDB: zeros, but did not yet use them in any way. But be careful: do not  
    140911 23:57:43 InnoDB: remove old data files which contain your precious data!  
    140911 23:57:43 [ERROR] Plugin 'InnoDB' init function returned error.  
    140911 23:57:43 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.  
    140911 23:57:43 [ERROR] Unknown/unsupported storage engine: InnoDB  
    140911 23:57:43 [ERROR] Aborting  


*****在5.6版本中：[版本：5.6.19]



    2014-09-11 22:20:01 1222 [ERROR] InnoDB: auto-extending data file ./ibdata1 is of a different size 65536 pages (rounded down to MB) than  
     specified in the .cnf file: initial 76800 pages, max 0 (relevant if non-zero) pages!  
    2014-09-11 22:20:01 1222 [ERROR] InnoDB: Could not open or create the system tablespace. If you tried to add new data files to the syste  
    m tablespace, and it failed here, you should now edit innodb_data_file_path in my.cnf back to what it was, and remove the new ibdata fil  
    es InnoDB created in this failed attempt. InnoDB only wrote those files full of zeros, but did not yet use them in any way. But be caref  
    ul: do not remove old data files which contain your precious data!  
    2014-09-11 22:20:01 1222 [ERROR] Plugin 'InnoDB' init function returned error.  
    2014-09-11 22:20:01 1222 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.  
    2014-09-11 22:20:01 1222 [ERROR] Unknown/unsupported storage engine: InnoDB  
    2014-09-11 22:20:01 1222 [ERROR] Aborting  


原来的ibdata1大小为：65536*8*2/1024=1024M=1G

当前ibdata1被修改为：76800*8*2/1024=1200M