gcs.check_appl_proto
Controls whether the node performs application-level protocol version checks when joining a cluster.
The wsrep_provider_options system variable applies to MariaDB Enterprise Cluster, powered by Galera and to Galera Cluster available with MariaDB Community Server. This page relates specifically to the gcs.check_appl_proto wsrep_provider_options.
Details
Galera Cluster automatically uses the highest protocol version supported by all nodes. This prevents older nodes, which lack support for newer features, from joining or disrupting the cluster until an upgrade solution is available.
However, MySQL and MariaDB have evolved differently, and their internal protocol versions are incomparable. This incompatibility prevents a mixed-node cluster (MySQL nodes and MariaDB nodes) from forming, which blocks rolling migrations.
Migration Usage: When migrating from a MySQL-based Galera cluster (e.g., Percona XtraDB Cluster) to MariaDB Galera Cluster, this parameter must be set to FALSE (OFF) on all nodes to disable the protocol check. Once the cluster is fully migrated to MariaDB, it should be set back to TRUE.
Known reporting issue in early versions
The variable may appear as OFF in plugins even though the default behavior is TRUE. Explicitly configure it to ensure the desired state during migration.
Default Value
TRUE
Dynamic
NO
Debug
NO
Examples
Display Current Value
wsrep_provider_options define optional settings the node passes to the wsrep provider.
To display current wsrep_provider_options values:
The expected output will display the option and the value. Options with no default value will not be displayed in the output.
Set in Configuration File
When changing a setting for a wsrep_provider_options in the config file, you must list EVERY option that is to have a value other than the default value. Options that are not explicitly listed are reset to the default value.
Options are set in the my.cnf configuration file. Use the ; delimiter to set multiple options.
The configuration file must be updated on each node. A restart to each node is needed for changes to take effect.
Use a quoted string that includes every option where you want to override the default value. Options that are not in the list will reset to their default value.
To set the option in the configuration file (example for migration):
Set Dynamically
The gcs.check_appl_proto option cannot be set dynamically. It can only be set in the configuration file.
Trying to change a non-dynamic option with SET results in an error:
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