Upgrading MariaDB MaxScale

Upgrading MariaDB MaxScale

For more information about what has changed, please refer to the ChangeLog and to the release notes.

Before starting the upgrade, any existing configuration files should be backed up.

Upgrading MariaDB MaxScale from 21.06 to 22.08

Removed Features

  • The support for legacy encryption keys generated with maxkeys from pre-2.5 versions has been removed. This feature was deprecated in MaxScale 2.5 when the new key storage format was introduced. To migrate to the new key storage format, create a new key file with maxkeys and re-encrypt the passwords with maxpasswd.

  • The deprecated Database Firewall filter has been removed.

Upgrading MariaDB MaxScale from 2.5 to 21.06

NOTE MaxScale 6.4 was renamed to 21.06 in May 2024. Thus, what would have been released as 6.4.16 in June, was released as 21.06.16. The purpose of this change is to make the versioning scheme used by all MaxScale series identical. 21.06 denotes the year and month when the first 6 release was made.

Duration Type Parameters

Using duration type parameters without an explicit suffix has been deprecated in MaxScale 2.4. In MaxScale 6 they are no longer allowed when used with the REST API or MaxCtrl. This means that any create or alter commands in MaxCtrl that use a duration type parameter must explicitly specify the suffix of the unit.

For example, the following command:

maxctrl alter service My-Service connection_keepalive 30000

should be replaced with:

maxctrl alter service My-Service connection_keepalive 30000ms

Duration type parameters can still be defined in the configuration file without an explicit suffix but this behavior is deprecated. The recommended approach is to add explicit suffixes to all duration type parameters when upgrading to MaxScale 6.

Changed Parameters


The default value of threads was changed to auto.

Removed Parameters

Core Parameters

The following deprecated core parameters have been removed:

  • thread_stack_size


The deprecated aliases for the schemarouter parameters ignore_databases and ignore_databases_regex have been removed. They can be replaced with ignore_tables and ignore_tables_regex.

In addition, the preferred_server parameter that was deprecated in 2.5 has also been removed.

Session Command History

The prune_sescmd_history, max_sescmd_history and disable_sescmd_history have been made into generic service parameters that are shared between all routers that support it.

The default value of prune_sescmd_history was changed from false to true. This was done as most MaxScale installations either benefit from it being enabled or are not affected by it.

Upgrading MariaDB MaxScale from 2.4 to 2.5


The deprecated MaxAdmin interface has been removed in 2.5.0 in favor of the REST API and the MaxCtrl command line client. The cli and maxscaled modules can no longer be used.


The credentials used by services now require additional grants. For a full list of required grants, refer to the protocol documentation.


The settings detect_stale_master, detect_standalone_master and detect_stale_slave are replaced by master_conditions and slave_conditions. The old settings may still be used, but will be removed in a later version.

Password encryption

The encrypted passwords feature has been updated to be more secure. Users are recommended to generate a new encryption key and and re-encrypt their passwords using the maxkeys and maxpasswd utilities. Old passwords still work.

Default Server State

The default state of servers in 2.4 was Running and in 2.5 it is now Down. This was done to prevent newly added servers from being accidentally used before they were monitored.

Columnstore Monitor

It is now mandatory to specify in the configuration what version the monitored Columnstore cluster is.


Please see the documentation for details.

New binlog router

The binlog router delivered with MaxScale 2.5 is completely new and not 100% backward compatible with the binlog router delivered with earlier MaxScale versions. If you use the binlog router, carefully assess whether the functionality provided by the new one fulfills your requirements, before upgrading MaxScale.

Tee Filter

The tee filter parameter service has been deprecated in favor of the target parameter. All usages of service can be replaced with target.

Upgrading MariaDB MaxScale from 2.3 to 2.4

Section Names

Reserved Names

Section and object names starting with @@ are now reserved for internal use by MaxScale.

In case such names have been used, they must manually be changed in all configuration files of MaxScale, before MaxScale 2.4 is started.

Those files are:

  • The main configuration file; typically /etc/maxscale.cnf.
  • All nested configuration files; typically /etc/maxscale.cnf.d/*.
  • All dynamic configuration files; typically /var/lib/maxscale/maxscale.cnd.d/*.

Whitespace in Names

Whitespace in section names that was deprecated in MaxScale 2.2 will now be rejected, which will cause the startup of MaxScale to fail.

To prevent that, section names like

[My Server]

[My Service]
servers=My Server

must be changed, for instance, to




Durations can now be specified using one of the suffixes h, m, s and ms for specifying durations in hours, minutes, seconds and milliseconds, respectively.

Not providing an explicit unit has been deprecated in MaxScale 2.4, so it is adviseable to add suffixes to durations. For instance,


Improved Admin User Encryption

MaxScale 2.4 will use a SHA2-512 hash for new admin user passwords. To upgrade a user to use the better hashing algorithm, either recreate the user or use the maxctrl alter user command.


The following settings have been removed and cause a startup error if defined:

  • mysql51_replication
  • multimaster
  • allow_cluster_recovery.


  • If multiple masters are available for a readwritesplit service, the one with the lowest connection count is selected.

  • If a master server is placed into maintenance mode, all open transactions are allowed to gracefully finish before the session is closed. To forcefully close the connections, use the --force option for maxctrl set server.

  • The lazy_connect feature can be used as a workaround to MXS-619. It also reduces the overall load on the system when connections are rapidly opened and closed.

  • Transaction replays now have a limit on how many times a replay is attempted. The default values is five attempts and is controlled by the transaction_replay_attempts parameter.

  • If transaction replay is enabled and a deadlock occurs (SQLSTATE 40XXX), the transaction is automatically retried.

Upgrading MariaDB MaxScale from 2.2 to 2.3

Increased Memory Use

Starting with MaxScale 2.3.0 up to 40% of the memory can be used for caching parsed queries. The most noticeable change is that it improves performance in almost all cases where queries need to be parsed. Most of the time this happens when the readwritesplit router or filters are used.

The amount of memory that MaxScale uses can be controlled with the query_classifier_cache_size parameter. For example, to limit the total memory to 1GB, add query_classifier_cache_size=1G to your configuration. To disable it, set the value to 0.

In addition to the aforementioned query classifier caching, the readwritesplit session command history is enabled by default in 2.3 but is limited to a maximum of 50 commands after which the history is disabled. This is unlikely to show in any metrics but it contributes to the increased memory foorprint of MaxScale.

Unknown Global Parameters

All unknown parameters are now treated as errors. Check your configuration for errors if MaxScale fails to start after upgrading to 2.3.1.

passwd is deprecated

In the configuration file, passwords for monitors and services should be specified using password; the support for the deprecated passwd will be removed in the future. That is, the following



should be changed to



authenticator_options for servers is ignored

Authenticator options are now only used with listeners.

Upgrading MariaDB MaxScale from 2.1 to 2.2

Administrative Users

The file format for the administrative users used by MaxScale has been changed. Old style files are automatically upgraded and a backup of the old file is stored in /var/lib/maxscale/passwd.backup.

Regular Expression Parameters

Modules may now use a built-in regular expression string parameter type instead of a normal string when accepting patterns. The modules that use the new regex parameter type are qlafilter and tee. When inputting pattern, enclose the string in slashes, e.g. match=/^select/ defines the pattern ^select.

Binlog Server

Binlog server automatically accepts GTID connection from MariaDB 10 slave servers by saving all incoming GTIDs into a SQLite map database.

MaxCtrl Included in Main Package

In the 2.2.1 beta version MaxCtrl was in its own package whereas in 2.2.2 it is in the main maxscale package. If you have a previous installation of MaxCtrl, please remove it before upgrading to MaxScale 2.2.2.

Upgrading MariaDB MaxScale from 2.0 to 2.1

IPv6 Support

MaxScale 2.1.2 added support for IPv6 addresses. The default interface that listeners bind to was changed from the IPv4 address to the IPv6 address ::. To bind to the old IPv4 address, add address= to the listener definition.

Persisted Configuration Files

Starting with MaxScale 2.1, any changes made with the newly added runtime configuration change will be persisted in a configuration file. These files are located in /var/lib/maxscale/maxscale.cnf.d/.

MaxScale Log Files

The name of the log file was changed from maxscaleN.log to maxscale.log. The default location for the log file is /var/log/maxscale/maxscale.log.

Rotating the log files will cause MaxScale to reopen the file instead of renaming them. This makes the MaxScale logging facility logrotate compatible.


The disable_sescmd_history option is now enabled by default. This means that slaves will not be recovered mid-session even if a replacement slave is available. To enable the legacy behavior, add the disable_sescmd_history=true parameter to the service definition.

Persistent Connections

The MariaDB session state is reset in MaxScale 2.1 for persistent connections. This means that any modifications to the session state (default database, user variable etc.) will not survive if the connection is put into the connection pool. For most users, this is the expected behavior.

User Data Cache

The location of the MariaDB user data cache was moved from /var/cache/maxscale/<Service> to /var/cache/maxscale/<Service>/<Listener>.

Galeramon Monitoring Algorithm

Galeramon will assign the master status only to the node which has a wsrep_local_index value of 0. This will guarantee consistent writes with multiple MaxScales but it also causes slower changes of the master node.

To enable the legacy behavior, add root_node_as_master=false to the Galera monitor configuration.

MaxAdmin Editing Mode

The default editing mode was changed from vim to emacs mode. To start maxadmin in the legacy mode, use the -i option.

Upgrading MariaDB MaxScale from 1.4 to 2.0


The default way the communication between MaxAdmin and MariaDB MaxScale is handled has been changed from an internet socket to a Unix domain socket. The former alternative is still available but has been deprecated.

If no arguments are given to MaxAdmin, it will attempt to connect to MariaDB MaxScale using a Unix domain socket. After the upgrade you will need to provide at least one internet socket related flag - -h, -P, -u or -p - to force MaxAdmin to use the internet socket approach.


user@host $ maxadmin -u admin

MySQL Monitor

The MySQL Monitor now assigns the stale state to the master server by default. In addition to this, the slave servers receive the stale slave state when they lose the connection to the master. This should not cause changes in behavior but the output of MaxAdmin will show new states when replication is broken.

Upgrading MaxScale from 1.3 to 1.4

Service user permissions

The service users now also need SELECT privileges on mysql.tables_priv. This is required for the resolution of table level grants. To grant SELECT privileges for the service user, replace the user and hostname in the following example.

GRANT SELECT ON mysql.tables_priv TO 'username'@'maxscalehost';

Password encryption

MaxScale 1.4 upgrades the used password encryption algorithms to more secure ones. This requires that the password files are recreated with the maxkeys tool. For more information about how to do this, please read the installation guide: MariaDB MaxScale Installation Guide


The SSL configuration parameters are now a part of the listeners. If a service used the old style SSL configuration parameters, the values should be moved to the listener which is associated with that service.

Here is an example of an old style configuration.



And here is the new, 1.4 compatible configuration style.



Please also note that the enabled SSL mode is no longer supported due to the inherent security issues with allowing SSL and non-SSL connections on the same port. In addition to this, SSLv3 is no longer supported due to vulnerabilities found in it.

Upgrading MaxScale from 1.2 to 1.3

Binlog Router

The master server details are now provided with a master.ini file located in the binlog directory and it can be changed using a CHANGE MASTER TO command issued via a MySQL connection to MaxScale.

This file, properly filled, is now mandatory and without it the binlog router cannot connect to the master database.

Before starting binlog router after MaxScale 1.3 upgrade, please add relevant information to master.ini, example:


Additionally, the option servers=masterdb in the service definition is no longer required.

Upgrading MaxScale from 1.1 to 1.2

This document describes upgrading MaxScale from version 1.1.1 to 1.2 and the major differences in the new version compared to the old version. The major changes can be found in the Changelog.txt file in the installation directory and the official release notes in the ReleaseNotes.txt file.


Upgrading MaxScale will copy the MaxScale.cnf file in /usr/local/mariadb-maxscale/etc/ to /etc/ and renamed to maxscale.cnf. Binary log files are not automatically copied and should be manually moved from /usr/local/mariadb-maxscale to /var/lib/maxscale/.

File location changes

MaxScale 1.2 follows the FHS-standard and installs to /usr/ and /var/ subfolders. Here are the major changes and file locations.

  • Configuration files are located in /etc/ and use lowercase letters: /etc/maxscale.cnf
  • Binary files are in /usr/bin/
  • Libraries and modules are in /usr/lib64/maxscale/. If you are using custom modules, please make sure they are in this directory before starting MaxScale.
  • Log files are in the var/log/maxscale/ folder
  • MaxScale's PID file is located in /var/run/maxscale/maxscale.pid
  • Data files and other persistent files are in /var/lib/maxscale/

Running MaxScale without root permissions

MaxScale can run as a non-root user with the 1.2 version. RPM and DEB packages install the maxscale user and maxscale group which are used by the init scripts and systemd configuration files. If you are installing from a binary tarball, you can run the postinst script included in it to manually create these groups.

Upgrading MaxScale from 1.0 to 1.1

This document describes upgrading MaxScale from version 1.0.5 to 1.1.0 and the major differences in the new version compared to the old version. The major changes can be found in the Changelog.txt file in the installation directory and the official release notes in the ReleaseNotes.txt file.


If you are installing MaxScale from a RPM package, we recommend you back up your configuration and log files and that you remove the old installation of MaxScale completely. If you choose to upgrade MaxScale instead of removing it and re-installing it afterwards, the init scripts in /etc/init.d folder will be missing. This is due to the RPM packaging system but the script can be re-installed by running the postinst script found in the /usr/local/mariadb-maxscale folder.

# Re-install init scripts
cd /usr/local/mariadb-maxscale

The 1.1.0 version of MaxScale installs into /usr/local/mariadb-maxscale instead of /usr/local/skysql/maxscale. This will cause external references to MaxScale's home directory to stop working so remember to update all paths with the new version.

MaxAdmin changes

The MaxAdmin client's default password in MaxScale 1.1.0 is mariadb instead of skysql.


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