natanael@slrpnk.net

You can start with timed bans, so they get the point

It counts as long as barriers are on

https://archive.kernel.org/oldwiki/ext4.wiki.kernel.org/index.php/Ext4_Howto.html#Barriers_on_by_default

External drives expect you to ensure writes complete first. If you don’t then smart software with copy-on-write and consistency checks can survive power loss (at the cost of losing recent changes). Other software which assumes a reliable drive can get wrecked.

Lots of file systems can not handle random power losses because they don’t force continous integrity of the disk file system, that’s why FAT formatted drives so often get corrupted

This depends entirely on the motherboard because many newer ones are fully capable of disconnecting the battery and maintaining it intelligently like smartphones does

I recommend a UPS, even a small one is fine for this. Spinning disks don’t like frequent starts and stops, especially not unplanned powerless ones.

At least you should be running a journaling file system or something similar which tolerates power loss decently (you’ll still see data corruption, but the file system won’t die). If you run software that doesn’t tolerate power loss well, then you absolutely need an UPS