SOLVED Freenas won't reboot after lost volume || Prepare a backup before you upgrade

[zokker13]

Hello there,

this year I wanted to start a bit cleaner. The new Update to the 11.2 legacy train has been out for a few days and I thought about updating.
So now I wanted to backup data first because you never know.

I dongled up some internal drive with SATA to usb3 and hook it up in the freenas web UI (aka creating a new pool with the single disk).
So far so good and I was able to get some first folders over. Then my stupid knee hit the USB connection and the drive disconnected. So the pool status was "UNAVAIL" and the disk was gone from the disk overview.

I then plugged the disk back and hoped it would connect itself but it didn't.
After that I decided to go through the "Replace disk" UI and force a reattach but that didn't help either - the UI reported some error I didn't save.

Patience is not my friend so I decided that a reboot might work so I initiated the reboot through the UI. The system wouldn't reboot. I can't connect through the UI. IPMI works and the screen shows this:

The question now is if the system is ever going to reboot on it's own or if I should hardreset it.
I'm really unsure how I should start it aswell. With the plugged-in usb drive or not?
The message itself tells me that the drives are synced and I could reboot safely but I'm not sure (though, I can't really do shit with the system at this point)

Are there any suggestion how to handle this and also how to handle this in the future? Obviously, the best would be to have an identical clone of the system but I don't feel like that yet.

Btw. I didn't trigger the update if that's a question you guys have.

Edit1: I restarted the system. It seemed stable enough in my eyes and it worked. My original pool is back and the data is accessable. But I'm still a bit confused in how I'd save the data of the "important" pool data. Would I just hook-up usb and create another pool? This really seems volatile as all my data on the disk is inaccessable - something destroyed the pool I assume.
It's a whole lot of assumptions I'm throwing around here. Sorry for that.
My next step is to do an old-school mount somewhere without creating a pool.

Edit2: Okay, seems like I've got ~something~ running now. I just have the usb drive act as a normal ufs partition and mount it in Linux when need comes up. However, the initial pool was lost and I suppose it's because I'm an idiot. I think I'm not supposed to create a zpool for something like an usb drive that is shared (shared because it's usb). A pool should have a proper structure with fault tolerance.

I'll write a little writeup later how to create the fs and mount it under Linux so this thread isn't as useless.

Edit3:
Okay, here's how I prepared the external disk to act as a backup before upgrading.
Here's what I have:
* Internal Drive
* USB dongle, SATA to USB3

1. ssh into your server as root
2. Put the hardware together and the usb into the server
3. Code:

   $ dmesg
   da1 at umass ...
   da1 <ID OF MANUFACTURER> ...
   ... (some more da1 lines)

4. Create a new GPT table on the disk (if need be) gpart create -s GPT da1 (the da1 part might change, mind the dmesg output!)
5. Create an ufs partition gpart add -t freebsd-ufs da1
6. Check if you are satisfied: gpart show da1
7. Create the filesystem: newfs -U /dev/da1
8. Create some folder to mount your drive to: /mnt/exusb1
9. Mount the drive: mount /dev/da1 /mnt/exusb1
10. - Now you rsync all your data to the drive -
11. When done, umount: umount /mnt/exusb1

The following describes a mounting to Archlinux:

1. Create some folder: mkdir /mnt/exusb1
2. Mount: mount /dev/sdb1 /mnt/exusb1 -t ufs -o ufstype=ufs2,ro (readonly because UFS seems unstable on Linux)
3. Copy your lost data

I hope this is helpful for one or another.

Edit4:
I've checked the resources and there's some fella who decided to create a little guide. It's far more advanced than this approach but you guys should check it out: https://forums.freenas.org/index.php?resources/how-to-backup-to-local-disks.26/