Working with Binary Logs¶
xtrabackup binary integrates with information that InnoDB
stores in its transaction log about the corresponding binary log
position for committed transactions. This enables it to print out the
binary log position to which a backup corresponds, so you can use it
to set up new replication replicas or perform point-in-time recovery.
Finding the Binary Log Position¶
You can find the binary log position corresponding to a backup once
the backup has been prepared. This can be done by either running the
xtrabackup with the
--apply-log-only option. If your backup is from a server
with binary logging enabled, xtrabackup will create a file named
xtrabackup_binlog_info in the target directory. This file
contains the binary log file name and position of the exact point in
the binary log to which the prepared backup corresponds.
You will also see output similar to the following during the prepare stage:
InnoDB: Last MySQL binlog file position 0 3252710, file name ./mysql-bin.000001 ... snip ... [notice (again)] If you use binary log and don't use any hack of group commit, the binary log position seems to be: InnoDB: Last MySQL binlog file position 0 3252710, file name ./mysql-bin.000001
This output can also be found in the
xtrabackup_binlog_pos_innodb file, but it is only correct when no other than XtraDB or InnoDB are used as storage engines.
If other storage engines are used (i.e. MyISAM), you should use the
xtrabackup_binlog_info file to retrieve the position.
The message about hacking group commit refers to an early implementation of emulated group commit in Percona Server for MySQL.
To perform a point-in-time recovery from an
xtrabackup backup, you should prepare and restore the backup, and then replay binary logs from the point shown in the
A more detailed procedure is found here.
Setting Up a New Replication Replica¶
To set up a new replica, you should prepare the backup, and restore it to the data directory of your new replication replica. Then in your
CHANGE MASTER TO command, use the binary log filename and position shown in the
xtrabackup_binlog_info file to start replication.
A more detailed procedure is found in How to setup a replica for replication in 6 simple steps with Percona XtraBackup.