Comment by MenhirMike

Periodic reminder to check if your backups are working, and if you can also restore them. It doesn't matter which file system or operating system you use, make sure to backup your stuff. In a way that's immune to ransomware as well, so not just a RAID-1/5/Z or another form of hot/warm storage (RAID is not a backup, it's an uptime/availability mechanism) but cold storage. (I snapshot and tar that snapshot every night, then back it up both on tape and in the cloud.)