Blue Iris

Can't see any way to get email alerts for such things as camera failures and disk write errors.
I recently had a drive fail on my NAS and it locked the drive as read only. It was in a raid 5 array. I didn't notice for 4 days and thus I only have stills for that period. no video.

I would have thought BlueIris would have sent me some emails to say it was having issues. I can't even find anywhere to set this up. Closest I got was on each camera but that seems only for motion detected.

isn't it under the status and logs window ( the L icon with an arrow ) under the messages tab, click the status alerts at the bottom.

Anturis is a nice free service for 5 probes.

I use it to check for external web connections to BI being good, the SSL cert being good
Memory
CPU
Temperature (I am using SMART disk temperature as a proxy)

Also, you can send many alerts on a cameras signal loss using 'Watchdog' tab in the cameras settings.