MySQL Backup and Restore

Sites that need an extra level of redundancy for their MySQL data can use the MySQL Binary Log and mysqldump. mysqldump is used to dump all the data in the database to a SQL script file. Data changes that occur later than the dumpfile are written to the binary log. If the database ever needs to be recovered, you can use the mysql command-line tool to load the data from the dump file and binary logs.

To configure binary logging, edit /opt/zimbra/conf/my.cnf and add the following line:

log-bin = <path>/<basename>

where <path> is the path to the directory that contains the binlogs and <basename> is the prefix of the binary log filenames. Binary log files should be placed on a separate disk device from the MySQL database files, so that they can be used for recovery if the database disk fails. After enabling the binary log, restart the mail server and MySQL with

$ zmstorectl restart

and check the binary log directory to make sure the logs are being written. Now set up a cron job that runs mysqldump on a scheduled basis:

/opt/zimbra/mysql/bin/mysqldump --all-databases --single-transaction --master-data  --flush-logs > <dump-file>.sql

where <dump-file> is the path to the MySQL dump file. Be sure to put the dump file on a separate disk device from the MySQL database files. Each time

If the database ever needs to be recovered, use the mysql command-line tool to load the dump file and binary log records. Make sure that the mail server is not running while you're performing the restore.

First, determine the first binlog file that needs to be replayed:

$ grep "CHANGE MASTER" dump.sql | head -1
CHANGE MASTER TO MASTER_LOG_FILE='binlog.000006', MASTER_LOG_POS=106;

Next, determine the last binlog file that needs to be replayed:

$ ls /opt/zimbra/binlog/binlog.0* | sort | tail -1
/opt/zimbra/binlog/binlog.000009

Flush the logs so that the binlog gets rotated, and the restore operations get written to binlog.000010:

$ mysqladmin flush-logs

Now restore the database dump:

$ mysql --user=root --password=XXX < dump.sql

Once the dump is restored, replay the binlog files 6-9:

$ mysqlbinlog /opt/zimbra/binlog/binlog.000006 | mysql --user=root --password=XXX
$ mysqlbinlog /opt/zimbra/binlog/binlog.000007 | mysql --user=root --password=XXX
$ mysqlbinlog /opt/zimbra/binlog/binlog.000008 | mysql --user=root --password=XXX
$ mysqlbinlog /opt/zimbra/binlog/binlog.000009 | mysql --user=root --password=XXX