| Variable | Versions | Values | Default | Unit | Comment |
| threads | 1.4 | | 2.3 | 2.4 | 2.5 | { <n> | auto } | 1 | thread | |
| thread_stack_size | | 2.2 | | | | <n> | | | Ignored and deprecated in 2.3 |
| rebalance_period | | | | | 2.5 | <n> | 0 | second | |
| rebalance_threshold | | | | | 2.5 | <n> | 20 | delta load | |
| rebalance_window | | | | | 2.5 | <n> | 10 | second | |
| auth_connect_timeout | 1.4 | 2.2 | 2.3 | 2.4 | | <n> | 3 | second | |
| auth_read_timeout | 1.4 | 2.2 | 2.3 | 2.4 | | <n> | 1 | second | Deprecated in 2.5 |
| auth_write_timeout | 1.4 | 2.2 | 2.3 | 2.4 | | <n> | 2 | second | Deprecated in 2.5 |
| query_retries | | | 2.3 | 2.4 | 2.5 | <n> | 1 | time | Added in 2.1.10, disabled by default until 2.3.0 |
| query_retry_timeout | | | 2.3 | 2.4 | 2.5 | | 5 | | |
| passive | | | 2.3 | 2.4 | 2.5 | | false | | |
| ms_timestamp | 1.4 | | 2.3 | 2.4 | 2.5 | { 0 | 1 } | 0 | - | |
| skip_permission_checks | | | 2.3 | 2.4 | 2.5 | { 0 | 1 } | 0 | | |
| syslog | 1.4 | | 2.3 | 2.4 | 2.5 | { 0 | 1 } | 1 | - | |
| maxlog | 1.4 | | 2.3 | 2.4 | 2.5 | { 0 | 1 } | 1 | - | |
| log_to_shm | 1.4 | | | | | { 0 | 1 } | 0 | - | Deprecated and ignored in 2.3.0 and newer |
| log_warning | 1.4 | | 2.3 | 2.4 | 2.5 | { 0 | 1 } | 1 | - | |
| log_notice | 1.4 | | 2.3 | 2.4 | 2.5 | { 0 | 1 } | 1 | - | |
| log_info | 1.4 | | 2.3 | 2.4 | 2.5 | { 0 | 1 } | 0 | - | |
| log_debug | 1.4 | | 2.3 | 2.4 | 2.5 | { 0 | 1 } | 0 | - | |
| log_warn_super_user | | | | | 2.5 | | false | | |
| log_messages | | | | | | | | | Deprecated, use log_notice instead |
| log_trace | | | | | | | | | Deprecated, use log_info instead |
| log_augmentation | 1.4 | | 2.3 | 2.4 | 2.5 | { 0 | 1 } | 0 | - | |
| log_throttling | | | 2.3 | 2.4 | 2.5 | { <n>, <n>, <n> } | 10, 1000, 10000 | time, millisecond, millisecond | |
| logdir | 1.4 | | 2.3 | 2.4 | 2.5 | <dirpath> | /tmp/ | - | |
| datadir | 1.4 | | 2.3 | 2.4 | 2.5 | <dirpath> | /home/user/maxscale_data/ | - | |
| libdir | 1.4 | | 2.3 | 2.4 | 2.5 | <dirpath> | /home/user/lib64/ | - | |
| cachedir | 1.4 | | 2.3 | 2.4 | 2.5 | <dirpath> | /tmp/maxscale_cache/ | - | |
| piddir | 1.4 | | 2.3 | 2.4 | 2.5 | <dirpath> | /tmp/maxscale_cache/ | - | |
| execdir | 1.4 | | 2.3 | 2.4 | 2.5 | <dirpath> | /usr/local/bin/ | - | |
| connector_plugindir | | | 2.3 | 2.4 | 2.5 | <dirpath> | /usr/lib/plugin/ | | |
| persistdir | | | 2.3 | 2.4 | 2.5 | <dirpath> | /var/lib/maxscale/maxscale.cnf.d/ | | |
| module_configdir | | | 2.3 | 2.4 | 2.5 | <dirpath> | /var/lib/maxscale/ | | |
| language | 1.4 | | 2.3 | 2.4 | 2.5 | <dirpath> | /home/user/lang/ | - | |
| query_classifier | | | 2.3 | 2.4 | 2.5 | <classifier> | qc_sqlite | | |
| query_classifier_cache_size | | | 2.3 | 2.4 | 2.5 | <n> | 15% of system Memory | byte | |
| query_classifier_args | | | 2.3 | 2.4 | 2.5 | | | | |
| substitute_variables | | | 2.3 | 2.4 | 2.5 | { true | false } | false | | |
| sql_mode | | | 2.3 | 2.4 | 2.5 | { default | oracle } | default | | |
| local_address | | | 2.3 | 2.4 | 2.5 | <IP address> | * | | |
| users_refresh_time | | | 2.3 | 2.4 | 2.5 | <n> | 30 | second | |
| user_refresh_interval | | | | 2.4 | 2.5 | <n> | 0 | second | |
| retain_last_statements | | | 2.3 | 2.4 | 2.5 | <n> | 0 | statement | |
| dump_last_statements | | | 2.3 | 2.4 | 2.5 | { on_error | on_close | never } | never | - | |
| session_trace | | | 2.3 | 2.4 | 2.5 | <n> | 0 | statement | |
| writeq_high_water | | | 2.3 | 2.4 | 2.5 | | | | |
| writeq_low_water | | | 2.3 | 2.4 | 2.5 | | | | |
| load_persisted_configs | | | 2.3 | 2.4 | 2.5 | { 0 | 1 } | 1 | | |
| max_auth_errors_until_block | | | | 2.4 | 2.5 | <n> | 10 | | |
| debug | | | | | 2.5 | | | | |
| admin_host | | | 2.3 | 2.4 | 2.5 | <IP address> | 127.0.0.1 | | |
| admin_port | | | 2.3 | 2.4 | 2.5 | <n> | 8989 | | |
| admin_auth | | | 2.3 | 2.4 | 2.5 | | 1 | | |
| admin_ssl_key | | | 2.3 | 2.4 | 2.5 | | | | |
| admin_ssl_cert | | | 2.3 | 2.4 | 2.5 | | | | |
| admin_ssl_ca_cert | | | 2.3 | 2.4 | 2.5 | | | | |
| admin_enabled | | | 2.3 | 2.4 | 2.5 | { 0 | 1 } | | | |
| admin_gui | | | | | 2.5 | | 1 | | |
| admin_secure_gui | | | | | 2.5 | | | | |
| admin_log_auth_failures | | | | 2.4 | 2.5 | { 0 | 1 } | 1 | | |
| admin_pam_readwrite_service | | | | 2.4 | 2.5 | | | | |
| admin_pam_readonly_service | | | | 2.4 | 2.5 | | | | |