If the load is too high, now not only the poller but also the page delivery will stop.

include/cronhooks.php

@@ -30,7 +30,7 @@ function cronhooks_run(&$argv, &$argc){
 	if(function_exists('sys_getloadavg')) {
 		$load = sys_getloadavg();
 		if(intval($load[0]) > $maxsysload) {
-			logger('system: load ' . $load . ' too high. Poller deferred to next scheduled run.');
+			logger('system: load ' . $load[0] . ' too high. Cronhooks deferred to next scheduled run.');
 			return;
 		}
 	}

include/delivery.php

@@ -60,7 +60,7 @@ function delivery_run(&$argv, &$argc){
 		if(function_exists('sys_getloadavg')) {
 			$load = sys_getloadavg();
 			if(intval($load[0]) > $maxsysload) {
-				logger('system: load ' . $load . ' too high. Delivery deferred to next queue run.');
+				logger('system: load ' . $load[0] . ' too high. Delivery deferred to next queue run.');
 				return;
 			}
 		}

include/poller.php

@@ -46,7 +46,7 @@ function poller_run(&$argv, &$argc){
 	if(function_exists('sys_getloadavg')) {
 		$load = sys_getloadavg();
 		if(intval($load[0]) > $maxsysload) {
-			logger('system: load ' . $load . ' too high. Poller deferred to next scheduled run.');
+			logger('system: load ' . $load[0] . ' too high. Poller deferred to next scheduled run.');
 			return;
 		}
 	}

index.php

@@ -53,6 +53,20 @@ if(!$install) {
 	load_config('config');
 	load_config('system');
 
+	$maxsysload = intval(get_config('system','maxloadavg'));
+	if($maxsysload < 1)
+		$maxsysload = 50;
+	if(function_exists('sys_getloadavg')) {
+		$load = sys_getloadavg();
+		if(intval($load[0]) > $maxsysload) {
+			logger('system: load ' . $load[0] . ' too high. Service Temporarily Unavailable.');
+			header($_SERVER["SERVER_PROTOCOL"].' 503 Service Temporarily Unavailable');
+			header('Retry-After: 300');
+			die("System is currently unavailable. Please try again later");
+		}
+	}
+
+
 	if (get_config('system','force_ssl') AND ($a->get_scheme() == "http") AND
 		(intval(get_config('system','ssl_policy')) == SSL_POLICY_FULL) AND
 		(substr($a->get_baseurl(), 0, 8) == "https://")) {