Yes when it comes to RAID, a UPS is a must.

Linux MDADM is not resiliency against power lose. And will overwrite from master if they are not equal.

Cow system ZFS, LVM, BTRFS and similar, have separate metadata table to compare against. But even then they can be affected by write hole in the event of a powerloss.

If you are thinking it for “backup” for redundancy in case of disc error, a solution can be to use something like borg backup, and a source disk as a BTRFS file system so you can be notified if there is checksum errors.

A cheap UPS is 60€, it will work good enough.

I think Bitwarden withorganizations will fit your needs.

Be burned out is more like trying to run a life long marathon at 125%, it works find in the start but at some point the body needs to recover.

The point to show the output is to help us understand your system. Not to point directly at the issue. Like for mount this will show what partition is mount where.

You system don’t have fdisk is installed.

To help you we need to understand your setup

• show us the output of ‘mount’
• show us the output of ‘lsblk’
• show us the output of ‘fdisk -l /dev/sda’
• Do you run snapshots?

If i am to get a new NAS I would get https://store.ui.com/us/en/products/unas-2