netdata monitors mount points but it automatically removes the charts and their alarms when they are unmounted. Now that I think of it, it would be nice to add an option in netdata.conf to disable that functionality for cases like yours. Please request it at github.
What you can do today, is to create a simple bash plugin for netdata that will monitor anything you like and send metrics to netdata. Then based on the values you send, you can create an alarm. So, for example you could monitor the number of mount points and report their number to netdata (i.e. mounts = 10), or you could create a chart for each mount point and attach an alarm template to each of them.
However, I think you should probably use fping
plugin to monitor the availability and the quality of the link between your servers. fping
charts at netdata already have plenty of alarms attached, so you will be notified immediately if the remote server is not reachable or the connection is slow. Check this: https://github.com/firehol/netdata/wiki/fping-Plugin