Seconded. Netdata has a generic and forgettable name but is powerful and easy to set up.

Open source, runs in docker or LXC. Web UI with more metrics than you will ever want, plus plugins. Support for alerts and some log aggregation, though I have not tried logging yet.

Who’s going to peer review that?

This means it’s working.

Guys you’re all wrong.

It’s PornHub.

Media failure isn’t the only reason to back up. If you delete a file on a RAID array, it’s gone on all disks. If you need to recover that deleted file, you can’t recover from RAID. The same goes for formatting/damage of the file system, recovery from something wrong inside a database, etc.