Click on OK when you’ve configured all of the appropriate administrators for alerting. Click on the Edit… button for Push and if Push notifications are not already enabled you will run through the Push Notification configuration wizard. Then, check the boxes for Email and Push for each of the alerts you want to receive (you don’t have to check both for each entry). Alerts have changed in OS X Server, they are no longer based on the SMART status of drives or capacity; instead Delivery is now based on service settings.
Finally, as with previous versions of OS X Server, EL Capitan Server has snmp built in. The configuration file for which is located in the /private/etc/snmp/snmpd.conf and the built-in LaunchDaemon is org.net-snmp.snmpd, where the actual binary being called is /usr/sbin/snmpd (and by default it’s called with a -f option). Once started, the default community name should be COMMUNITY (easily changed in the conf file) and to test, use the following command from a client (the client is 192.168.210.99 in the following example):
snmpwalk -On -v 1 -c COMMUNITY 192.168.210.99