diff --git a/status/query-monitor.pl b/status/query-monitor.pl
index 994977f30..fba8c38c6 100755
--- a/status/query-monitor.pl
+++ b/status/query-monitor.pl
@@ -1,30 +1,69 @@
 # query-monitor.pl
-# Try an SQL query on a MySQL or PostgreSQL server
+# Try an SQL query on a database server
 
-my %allowed_query_drivers = map { $_, 1 } ("mysql", "Pg", "Oracle");
+# SQL drivers offered in the UI and permitted by strict validation.
+my @query_driver_options = (
+	[ "mysql", "MySQL" ],
+	[ "MariaDB", "MariaDB" ],
+	[ "Pg", "PostgreSQL" ],
+	[ "Oracle", "Oracle" ]
+	);
+my %allowed_query_drivers = map { $_->[0], 1 } @query_driver_options;
 
+# canonical_query_driver(driver)
+# Normalize a stored driver name to the canonical DBI driver key.
+sub canonical_query_driver
+{
+my ($driver) = @_;
+# Accept legacy lowercase value while storing/using canonical DBI name.
+return $driver eq 'mariadb' ? 'MariaDB' : $driver;
+}
+
+# query_driver_candidates(driver)
+# Returns preferred and fallback DBI driver names for the selected driver.
+sub query_driver_candidates
+{
+my ($driver) = @_;
+$driver = &canonical_query_driver($driver);
+# Match mysql/mysql-lib.pl behavior : prefer selected family, then fallback.
+return ($driver eq 'mysql') ? ( "mysql", "MariaDB" ) :
+       ($driver eq 'MariaDB') ? ( "MariaDB", "mysql" ) :
+				( $driver );
+}
+
+# get_query_status(&service)
+# Attempts DB connect and query execution and returns monitor status hash.
 sub get_query_status
 {
-if (!$allowed_query_drivers{$_[0]->{'driver'}}) {
+my $driver = &canonical_query_driver($_[0]->{'driver'});
+if (!$allowed_query_drivers{$driver}) {
 	return { 'up' => -1,
 		 'desc' => &text('query_edriver',
-				 "<tt>DBD::$_[0]->{'driver'}</tt>") };
+				 "<tt>DBD::$driver</tt>") };
 	}
 
 # Load the driver
 local $drh;
-eval <<EOF;
-use DBI;
-\$drh = DBI->install_driver(\$_[0]->{'driver'});
-EOF
+eval { require DBI; };
 if ($@) {
 	return { 'up' => -1,
 		 'desc' => &text('query_edriver',
-				 "<tt>DBD::$_[0]->{'driver'}</tt>") };
+				 "<tt>DBD::$driver</tt>") };
+	}
+my @drivers = &query_driver_candidates($driver);
+# Try fallback-compatible drivers to tolerate either DBD::mysql or DBD::MariaDB.
+foreach my $try (@drivers) {
+	eval { $drh = DBI->install_driver($try); };
+	last if (!$@ && $drh);
+	}
+if (!$drh) {
+	return { 'up' => -1,
+		 'desc' => &text('query_edriver',
+				 "<tt>DBD::$driver</tt>") };
 	}
 
 # Connect to the database server
-local $dbistr = &make_dbistr($_[0]->{'driver'}, $_[0]->{'db'}, $_[0]->{'host'});
+local $dbistr = &make_dbistr($driver, $_[0]->{'db'}, $_[0]->{'host'});
 local $dbh = $drh->connect($dbistr,
                            $_[0]->{'user'}, $_[0]->{'pass'}, { });
 if (!$dbh) {
@@ -53,13 +92,13 @@ if ($_[0]->{'result'} ne '' && $r[0] ne $_[0]->{'result'}) {
 return { 'up' => 1 };
 }
 
+# show_query_dialog(&service)
+# Displays the SQL query monitor configuration form fields.
 sub show_query_dialog
 {
 print &ui_table_row($text{'query_driver'},
-	&ui_select("driver", $_[0]->{'driver'},
-		   [ [ "mysql", "MySQL" ],
-		     [ "Pg", "PostgreSQL" ],
-		     [ "Oracle", "Oracle" ] ]));
+	&ui_select("driver", &canonical_query_driver($_[0]->{'driver'}),
+		   \@query_driver_options));
 
 print &ui_table_row($text{'query_db'},
 	&ui_textbox("db", $_[0]->{'db'}, 20));
@@ -81,16 +120,26 @@ print &ui_table_row($text{'query_result'},
 			$text{'query_ignore'}), 3);
 }
 
+# parse_query_dialog(&service)
+# Validates query monitor inputs and stores normalized settings.
 sub parse_query_dialog
 {
-$allowed_query_drivers{$in{'driver'}} ||
-	&error(&text('query_edriver', "<tt>DBD::$in{'driver'}</tt>"));
-eval {
-	require DBI;
-	DBI->install_driver($in{'driver'});
-	};
-&error(&text('query_edriver', "<tt>DBD::$in{'driver'}</tt>")) if ($@);
-$_[0]->{'driver'} = $in{'driver'};
+my $driver = &canonical_query_driver($in{'driver'});
+$allowed_query_drivers{$driver} ||
+	&error(&text('query_edriver', "<tt>DBD::$driver</tt>"));
+eval { require DBI; };
+&error(&text('query_edriver', "<tt>DBD::$driver</tt>")) if ($@);
+my $ok;
+foreach my $try (&query_driver_candidates($driver)) {
+	# Validation mirrors runtime loading : any valid fallback driver is accepted.
+	eval { DBI->install_driver($try); };
+	if (!$@) {
+		$ok = 1;
+		last;
+		}
+	}
+&error(&text('query_edriver', "<tt>DBD::$driver</tt>")) if (!$ok);
+$_[0]->{'driver'} = $driver;
 
 $in{'db'} =~ /^\S+$/ || &error($text{'query_edb'});
 $_[0]->{'db'} = $in{'db'};
@@ -122,11 +171,14 @@ else {
 	}
 }
 
+# make_dbistr(driver, database, host)
+# Builds the DBI connection string for the selected SQL driver.
 sub make_dbistr
 {
 local ($driver, $db, $host) = @_;
 local $rv;
-if ($driver eq "mysql") {
+if ($driver eq "mysql" || $driver eq "MariaDB") {
+	# Both DBI drivers use "database=" style DSN here.
 	$rv = "database=$db";
 	}
 elsif ($driver eq "Pg") {
@@ -140,5 +192,3 @@ if ($host) {
 	}
 return $rv;
 }
-
-