External HDD not visible in VM anymore

rosbergsessa420

New Member
Aug 17, 2022
2
0
1
Hi. New to proxmox and linux in general so please bear with me.

We have a server which runs Proxmox as base, then there's two Windows VM's on it, for remote desktops etc.

This server has an external HDD hooked to it, which one of the Windows installs uses as backup destination. This Windows install was perfectly doing the backup on this drive, until 26/june, then Cobian Backup started returning "can't create directory". I find out that within this VM, I just can't see the hard drive anymore.

The disk does show up on "disks" and it's called /dev/sdc: https://i.imgur.com/VJgfdS6.png

Ths disk does NOT show up on "storage" (should it?): https://i.imgur.com/ZxL3QYO.png

Yes I've read the manual, yes I've done my research but all guides are pretty confusing, and they only show how to add the disk from scratch, re-format, re-everything, which obviously isn't what I need because this disk contains backups, so I need to be able to re-add it as it was. Somebody can guide me into this in a more noob-friendly way? Ofc I aim to learn this OS properly with some time, it just happens that I'm new in this company and we need the problem fixed now, and this is the way the server was made.

Any help is welcome.
 

Dunuin

Famous Member
Jun 30, 2020
8,062
2,009
149
Germany
Ths disk does NOT show up on "storage" (should it?): https://i.imgur.com/ZxL3QYO.png
Usually not when passing through to a VM.

You didn't told us how you used that disk inside the VM. Guest OSs can't access any physical hardware of the host unless you use some kind of passthrough. As its a USB disk I would guess yoou either used USB passthrough (which isn't great as it is slow because its fully emulated and also nlt that reliable) or disk passthrough (like described here: https://pve.proxmox.com/wiki/Passthrough_Physical_Disk_to_Virtual_Machine_(VM) which by the way the guest OS will only see a virtual disks and not the real physical disk).

So first you should show us the VMs config file with qm config YourVMsVMID so we can see how you setup that USB disk.

My guess would be that you used disk passthrough with "/dev/sdd" or something similar and now that disk is called /dev/sdc because the old /dev/sdc got removed...or something similar.
 

rosbergsessa420

New Member
Aug 17, 2022
2
0
1
Usually not when passing through to a VM.

You didn't told us how you used that disk inside the VM. Guest OSs can't access any physical hardware of the host unless you use some kind of passthrough. As its a USB disk I would guess yoou either used USB passthrough (which isn't great as it is slow because its fully emulated and also nlt that reliable) or disk passthrough (like described here: https://pve.proxmox.com/wiki/Passthrough_Physical_Disk_to_Virtual_Machine_(VM) which by the way the guest OS will only see a virtual disks and not the real physical disk).

So first you should show us the VMs config file with qm config YourVMsVMID so we can see how you setup that USB disk.

My guess would be that you used disk passthrough with "/dev/sdd" or something similar and now that disk is called /dev/sdc because the old /dev/sdc got removed...or something similar.
"You didn't told us how you used that disk inside the VM."
I don't know how this was done, because it was done by a previous sys-admin, so apart from resolving the issue I also need to figure out how they did it before.

After some reading I've come to the conclusion that the disk was effectively passed through, and if not, that's the way I want to set it up nonetheless.

I tried the following instructions: https://pve.proxmox.com/wiki/Passthrough_Physical_Disk_to_Virtual_Machine_(VM)

But I really don't know what to do in there, I've figured out my disk is usb-WD_Elements_25A2_57585331413938394A305430-0:0 and tried the steps in "update configuration" but I get :

Error Configuration file 'nodes/proxmox01/qemu-server/100.conf' does not exist​


where to go now?
 

Dunuin

Famous Member
Jun 30, 2020
8,062
2,009
149
Germany
Sounds like you are running a cluster. Also keep in mind that you can't migrate guests between nodes when using passthrough. Might be better to backup to a NAS or PBS.

What command did you use? You still did't showed us your VMs config file.
 

About

The Proxmox community has been around for many years and offers help and support for Proxmox VE, Proxmox Backup Server, and Proxmox Mail Gateway.
We think our community is one of the best thanks to people like you!

Get your subscription!

The Proxmox team works very hard to make sure you are running the best software and getting stable updates and security enhancements, as well as quick enterprise support. Tens of thousands of happy customers have a Proxmox subscription. Get your own in 60 seconds.

Buy now!