Dynamic recreation of InnoDB redo logs

MySQL 5.6 will now automatically recreate the InnoDB redo log files during a MySQL restart if the size (or number) of these logs changes, i.e. a change to innodb_log_file_size. See Changing the Number or Size of InnoDB Log Files which states “If InnoDB detects that the innodb_log_file_size differs from the redo log file size, it will write a log checkpoint, close and remove the old log files, create new log files at the requested size, and open the new log files.”

Before MySQL 5.6 it was necessary to stop MySQL and remove the InnoDB log files manually before restarting MySQL.

The error log shows:

tail -f /mysql/log/error.log
...
2015-03-28 21:51:25 3767 [Warning] InnoDB: Resizing redo log from 2*3072 to 2*65536 pages, LSN=1626017
2015-03-28 21:51:25 3767 [Warning] InnoDB: Starting to delete and rewrite log files.
2015-03-28 21:51:25 3767 [Note] InnoDB: Setting log file ./ib_logfile101 size to 1024 MB
InnoDB: Progress in MB: 100 200 300 400 500 600 700 800 900 1000
2015-03-28 21:51:28 3767 [Note] InnoDB: Setting log file ./ib_logfile1 size to 1024 MB
InnoDB: Progress in MB: 100 200 300 400 500 600 700 800 900 1000
2015-03-28 21:51:31 3767 [Note] InnoDB: Renaming log file ./ib_logfile101 to ./ib_logfile0
2015-03-28 21:51:31 3767 [Warning] InnoDB: New log files created, LSN=1626017
...

It was however odd that MySQL had indicated it had successfully started but the underlying Redo log files were not complete and in-place as seen by the following directory listings.

$ sudo service mysql start
......
 * MySQL Community Server 5.6.23 is started
$

$ ls -lh /var/lib/mysql/
total 1.9G
-rw-rw---- 1 mysql mysql   56 Mar 28 19:42 auto.cnf
-rw-rw---- 1 mysql mysql  12M Mar 28 21:51 ibdata1
-rw-rw---- 1 mysql mysql 902M Mar 28 21:51 ib_logfile1
-rw-rw---- 1 mysql mysql 1.0G Mar 28 21:51 ib_logfile101
drwxr-x--- 2 mysql mysql 4.0K Mar 28 19:42 mysql
drwx------ 2 mysql mysql 4.0K Mar 28 19:42 performance_schema

$ ls -lh /var/lib/mysql/
total 2.1G
-rw-rw---- 1 mysql mysql   56 Mar 28 19:42 auto.cnf
-rw-rw---- 1 mysql mysql  12M Mar 28 21:51 ibdata1



    
  -rw-rw---- 1 mysql mysql 1.0G Mar 28 21:51 ib_logfile0
  -rw-rw---- 1 mysql mysql 1.0G Mar 28 21:51 ib_logfile1
  drwxr-x--- 2 mysql mysql 4.0K Mar 28 19:42 mysql
  drwx------ 2 mysql mysql 4.0K Mar 28 19:42 performance_schema
Tagged with: Databases My.cnf MySQL

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