A tray-based, Linux RAID monitor I made for easy visual indication of my mdadm RAID1 status.
(Made using Qt 5 on QtCreator 4.6.2 and tested on Ubuntu with KDE 5.44/Plasma 5.12 ... but never quite finished or used significantly then or since; I actually ended up switching from RAID to rsync.)
It sits in your tray, showing a
if no RAID is detected (initial, pre-scan state),
if a RAID is faulty, or
if all RAIDs are good (or recovering).
Instead of having to manually do cat /proc/mdstat, it calls and reads it for you! By default, it does this at an interval of 1 minute, set in the QTimer scanTimer.
Since this is for mdadm RAIDs, it uses the syntax of the mdstat file to watch for faulty RAIDs via the presence of tokens like "[U_]" or "(F)". When detecting one, its tray icon starts blinking red and it sends a notification every 15 minutes (interval set in notifyTimer) listing the faulty devices. These can be disabled in the tray icon's context menu.