I have a computer running what I think at the time was called Ubuntu Server (no GUI) that I installed Xfce on, making it essentially Xubuntu. I did this because it allowed me to use mdadm to set up RAID (4 drives; RAID 5) during the OS install.

My OS lives on an NVME drive, and I have my raid mounted at /Files.

I have lots of data in my RAID, and much (but not all!) is backed up to the cloud. There would be both emotional issues and lots of time required to fix things if I lose the RAID or the data on it.

(I am realizing as I write this that I put off upgrading so long, I can probably copy all the data to one 20TB drive (oof! That’s expensive) since they’ve gotten about as big as my 21.83TB volume.)

How safe is it to take the OS up on this offer?

New release '20.04.6 LTS' available.
Run 'do-release-upgrade' to upgrade to it.

How hard is it to reestablish the RAID if it forgets it exists?

Is there anything else I can do to make this more likely to “just work”? (Like: don’t do it over ssh)

Are there other factors I am not thinking of?