[PLUG] Raving mad RAID

[John Jason Jordan]

About a week ago I finally was successful in creating a RAID0 array on
my four NVMe drives that are installed in a Thunderbolt 3 enclosure.
After creating the array it appeared in /dev as md0. After rebooting it
became md127. I copied the UUID from Gparted and used it in a line
that I added to /etc/fstab.

The array has been working fine ever since I created it, including
copying files to it late last night. This morning I tried to add a
torrent for a distro ISO to Ktorrent, and got an error message that
Ktorrent couldn't add the torrent because the location to copy it to
did not exist. WTH?

I looked at my GUI file manager and all the files in the array were
listed. I right-clicked on one of them and immediately noticed that
Rename and Delete were no longer listed in the options. After a bit
more poking around I determined that the array had become read-only
overnight.

I decided to umount it and then re-mount it. The umount command gave me
'can't read superblock on /dev/md127p1,' which is what /dev/md0 became
after rebooting a week ago. However, apparently the umount command
succeeded, because it was no longer mounted. Then I tried to re-mount
it and got the same superblock error message.

Looking at /dev I see that most everything has changed. NVMe1-3 now
have namespace 2 instead of the 1 that they were when I created the
array. And now nvme5-8 are listed, which don't exist. And only nvme4n1
had a partition after I created the array, and now it has two
partitions.

It looks like I'm going to have to nuke the array, re-make it, and wait
24 hours to copy the 10TB of data back to the new array from the NAS
backup. But before I do that I need to find out what went wrong. Might
there be a defect in one of the NVMe drives? Or might there be a bug in
mdadm when it tries to create an array out of NVMe media? Or when the
ext4 filesystem was created? I assume that there exists a utility to
check a drive, but I've never done that before. Suggestions?

I'm considering throwing my computers into the river and doing
something useful with my life.