August 23, 2014

Backing up binary log files with mysqlbinlog

Backing up binary logs are essential part of creating good backup infrastructure as it gives you the possibility for point in time recovery. After restoring a database from backup you have the option to recover changes that happend after taking a backup. The problem with this approach was that you had to do periodic filesystem level backups of the binary log files which could still lead to data loss depending on the interval you back them up.
Recently in MySQL 5.6, mysqlbinlog got a new feature addition that supports connecting to remote MySQL instances and dumping binary log data to local disks ( http://dev.mysql.com/doc/refman/5.6/en/mysqlbinlog-backup.html ). This can be used as a foundation of our live binary log backups.

The wrapper script below will connect to the remote server specified in the config and ensure mysqlbinlog utility is up and running. By default if you do not supply the binary log file, mysqlbinlog deletes and overwrites them all that is undesired behaviour in our case, so we have to supply the name of the last binary log. This last file will be still overwritten hence we make a backup first.

Configuration file:

Starting in the background with logging to /var/log/livebinlog/server2.log:

As a great addition, older logfiles that have been rotated can be checked against the MySQL server’s version if they are the same or not. For this purpose you can use rsync in “dry-run” mode.

Please note MySQL 5.6 is not yet released as GA but you can use mysqlbinlog to backup MySQL 5.1 and 5.5 databases.

Comments

  1. LinuxJedi says:

    I’d almost forgot I created that feature, it was quite a while ago. Thans for the coverage of it :)

  2. This would also work as an audit vault for database changes.

  3. John Phelps says:

    Many thanks – I’m right there developing my homebrew backup system. Your script ran straight out of the box for me – thanks again. I get this notice: “nohup: ignoring input and redirecting stderr to stdout”. Google says something about standard error, standard output and nohup.out but it’s a bit above my paygrade.

  4. Kagaruki says:

    Many thanks for this add, i have tried this on my production system all went well with one exception, once all the binlogs has been backed up and we re remained with the last one we start having multiple backups of the same binlog just identified with timestamp is this how its men’t to do?

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