Template:ZRM Pre-installation Checks

MySQL server requirements

The MySQL Server refers the database server being backed up by the ZRM for MySQL Server, which also called the ZRM Server.

• Verify that the version(s) of MySQL server(s) that you deploy are supported by Zmanda Recovery Manager for MySQL. See Tested Platforms for details.

ZRM for MySQL Server requirements

Verify that an operating system mysql user and a mysql group exist on the ZRM server.

• ZRM for MySQL requires the MySQL client commands listed below to be installed on the ZRM server. ZRM uses the following MySQL commands on the ZRM server:
  • mysqladmin
  • mysqlhotcopy
  • mysqldump
  • mysqlbinlog
  • mysql

• The MySQL client commands installed on the ZRM server should be compatible with version of MySQL servers being backed up. Zmanda recommends that the same version of MySQL software is used on the ZRM server and MySQL server.

• Check that MySQL client commands are installed in /usr/bin/ . If they are not, you must change the configuration of the client command location and binary log location in {{web.html($Config_method)}}. See the MySQL subsection of the {{web.html($BS_Config_method)}} for details.

• Two perl modules are necessary for MySQL ZRM. See the Perl installation notes section of the manual.
  • perl-DBI
  • perl-XML-Parser

• mailx mail package must be installed on the ZRM server. mailx can be found as part of the OS distribution. The mailx package must be configured to send mail from the ZRM machine to the MySQL database backup administrator.

MySQL Backup User

mysql> GRANT LOCK TABLES, SELECT, FILE, RELOAD, SUPER
     -> ON expenses.*
     -> TO 'dba-backup'@'server.company.com'
     -> IDENTIFIED BY 'obscure';

Binary Logs

Incremental backups of MySQL require binary logging enabled on the MySQL server. Start the MySQL server daemon (mysqld) with the --log-bin option:

mysqld --log-bin=BinLogFilename

Note: Enabling binary logs on a MySQL server reduces performance by about 1%.

It is good idea to store binary logs in a file system (storage) in a different file system than the file system containing the database directories.

Consult MySQL reference manual for more information on MySQL binary logs.

Backups Using Snapshots

ZRM for MySQL can create temporary snapshots of the filesystems or storage volumes and use these snapshot volumes to do backups. Because snapshots to disk are faster than backups to other media, this reduces the time that database tables must be locked. The snapshots are removed when backups are completed. Snapshots help to create a consistent copy of the MySQL database as the consistency is ensured before the snapshot is taken. Snapshot backup method scales well with size of database.

If the MySQL databases or tables use only transactional storage engines such as InnoDB, the time the application is locked reduced.

While taking snapshots of databases or tables that use non-transactional storage engines such as MyISAM, ZRM for MySQL flushes the database pages to the disk and obtains a read lock on the database(s) / table(s). The read lock is held only for a moment.

The file system I/O is stopped before taking a snapshot when the database resides on the file systems that support freeze/thaw operations such as XFS, VxFS (Veritas file systems).

Snapshots of LVM (logical volume manager) in Linux platforms, VxFS (Veritas filesystems), VSS (Volume Shadow Services) on Windows, Snap Manager (on Network Appliance filers), ZFS on Solaris platforms are supported.

All MySQL database files (data, log, indexes) must be stored in snapshot capable storage volumes. If any of the files are not on snapshot cable storage volumes, snapshot backup method will not be used. Instead, raw backup via mysqlhotcopy is performed.

SSL Between MySQL Servers and ZRM server

SSL provides an additional layer of security while moving backups over a network. We recommended that you enable SSL on the MySQL server if the backups are performed on unsecured networks. Installing SSL between the local ZRM for MySQL server and remote MySQL server(s) is necessary only for logical backups of remote MySQL servers.

To verify the availability of SSL support in the MySQL server, you can either:

• Run the following command on the local server:

# mysqld --ssl --help

When the SSL support does not exist, the system responds with a message like this:

060828 15:25:08 [ERROR] mysqld: unknown option '--ssl'

• Examine the value of the have_openssl system variable:

mysql> SHOW VARIABLES LIKE 'have_openssl';

+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| have_openssl  | YES   |
+---------------+-------+

Consult the MySQL reference manual for configuring SSL on MySQL.

Zmanda recommends using either of the two options given below to configure SSL when remote backups of MySQL servers done using unsecured networks.

• Set SSL parameters in the my.cnf file of MySQL on the ZRM server.

 ssl-ca=mySQL_conf_dir/openssl/cacert.pem
 ssl-cert=mySQL_conf_dir/openssl/client-cert.pem
 ssl-key=mySQL_conf_dir/openssl/client-key.pem

• Set SSL parameters for all backup set in mysql-zrm.conf file of ZRM for MySQL.

 ssl-options="--ssl --ssl-ca=mySQL_conf_dir/openssl/cacert.pem
                    --ssl-cert=mySQL_conf_dir/openssl/client-cert.pem        
                    --ssl-key=mySQL_conf_dir/openssl/client-key.pem"