Read data from existing disk (thin-volume)

[paranoidnemo]

Hi,
I'm pretty new to Proxmox and I've a question related to my new installation.
I've a minipc with 2 disks; at the moment of installation one disk was empty (new) the other was the data disk from my old dietpi (raspberry pi4B) installation.
I've installed Proxmox on the new disk with the idea of mounting the secondary one afterward to the host and give access to the data to all the VM/container but after installation i get two pve (on the running host the other a pve-OLD) and doesn't seems that i can access the data that are still on the secondary disk.
For sure I've done something the wrong way but I'll like to access the data; it is possible?
I'll also like to know if after recovering the data (if possible) to use the disk like I described above, I have to format it (I was thinking ext4) or I can just leaving it like that.

Any help is appriciated.

Thanks in advance,

 

[leesteken]

LVM does not support multiple VGs with the same name. That's why the installer renamed the existing pve to pve-OLD. (Assuming you had a Proxmox installed on that drive but that's weird since official Proxmox VE does not support ARM systems like Pi.)
In principle you could activate the pve-OLD and mount the LVs that are still there. What kind of data do you want to recover? I suggest learning about LVM a bit.
Virtual disks (without the VM configurations) can be moved to the new storage if you Add the pve-OLD as a LVM Storage to the (new) Proxmox. They can then also be connected to existing VMs using Reassign Owner.
After you saved your data from that drive, I would suggest wiping it and creating a new storage of your choice (with a different name).

 

[paranoidnemo]

That's the thing, I didn't install proxmox on raspberry. I'd a dietpi installation on the SD card of the raspberry and the disk was mounted as external USB disk using the dietpi tool to format and mount disks (I assume that the tool create a LVM on that disk for whatever reason). I've my Plex server data and some other stuff but nothing really critical. I would just prefer to recover to not spend a lot of time ripping all my CD again.
So if I understand it correctly you suggest to connect the old pve to the new proxmox instance, than mount the disks inside a VM to access and recover the data? Can I have a link at the documentation to do that? I really doesn't know much about LVM, I've to learn it for sure.
And yes, I for sure will format everything afterward.

 

[Impact]

Connect the drives and then share this

lsblk -o+FSTYPE,LABEL,MODEL
pvs
vgs
lvs
cat /etc/pve/storage.cfg.

You can re-add the old pool via Datacenter > Storage > Add > LVM-Thin. qm rescan and pct rescan can help adding existing drives to matching guests.

 

[leesteken]

Maybe the installer simply renames all existing VGs? Or maybe you had trouble installing Proxmox and accidentally installed it twice (I hope not, as that would have destroyed the original data)?

I'm assuming that some other software created the LVM VG (which is now named pve-OLD) on the second drive. Then you should not add it as a Storage to Proxmox. Use the Linux command line to activate the VG and mount the relevant LVs and copy the data to some place else. I don't have much active knowledge about LVM (since I use ZFS) but I'm sure someone else can help you with this as it is not specific (or related) to Proxmox.

 

[paranoidnemo]

Connect the drives and then share this

lsblk -o+FSTYPE,LABEL,MODEL
pvs
vgs
lvs
cat /etc/pve/storage.cfg.

You can re-add the old pool via Datacenter > Storage > Add > LVM-Thin. qm rescan and pct rescan can help adding existing drives to matching guests.

thanks for the answer, here what you asked for

first command: sda is where proxmox is installed, sdb is the secondary disk

NAME                        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS FSTYPE     LABEL MODEL
sda                           8:0    0 465.8G  0 disk                              Samsung
├─sda1                        8:1    0  1007K  0 part                             
├─sda2                        8:2    0     1G  0 part /boot/efi   vfat             
└─sda3                        8:3    0   464G  0 part             LVM2_membe       
  ├─pve-swap                252:0    0     8G  0 lvm  [SWAP]      swap             
  ├─pve-root                252:1    0    96G  0 lvm  /           ext4             
  ├─pve-data_tmeta          252:4    0   3.4G  0 lvm                               
  │ └─pve-data-tpool        252:8    0 337.1G  0 lvm                               
  │   ├─pve-data            252:9    0 337.1G  1 lvm                               
  │   └─pve-vm--100--disk--0
  │                         252:11   0     2G  0 lvm              ext4             
  └─pve-data_tdata          252:5    0 337.1G  0 lvm                               
    └─pve-data-tpool        252:8    0 337.1G  0 lvm                               
      ├─pve-data            252:9    0 337.1G  1 lvm                               
      └─pve-vm--100--disk--0
                            252:11   0     2G  0 lvm              ext4             
sdb                           8:16   0 476.9G  0 disk                              Vi560 S
├─sdb1                        8:17   0  1007K  0 part                             
├─sdb2                        8:18   0     1G  0 part             vfat             
└─sdb3                        8:19   0   475G  0 part             LVM2_membe       
  ├─pve--OLD--69E16B08-swap 252:2    0     8G  0 lvm              swap             
  ├─pve--OLD--69E16B08-root 252:3    0    96G  0 lvm              ext4             
  ├─pve--OLD--69E16B08-data_tmeta
  │ │                       252:6    0   3.5G  0 lvm                               
  │ └─pve--OLD--69E16B08-data
  │                         252:10   0 347.9G  0 lvm                               
  └─pve--OLD--69E16B08-data_tdata
    │                       252:7    0 347.9G  0 lvm                               
    └─pve--OLD--69E16B08-data
                            252:10   0 347.9G  0 lvm

root@prx:~# pvs
  PV         VG               Fmt  Attr PSize    PFree
  /dev/sda3  pve              lvm2 a--  <464.00g 16.00g
  /dev/sdb3  pve-OLD-69E16B08 lvm2 a--  <475.00g 16.00g

root@prx:~# vgs
  VG               #PV #LV #SN Attr   VSize    VFree
  pve                1   4   0 wz--n- <464.00g 16.00g
  pve-OLD-69E16B08   1   3   0 wz--n- <475.00g 16.00g

root@prx:~# lvs
  LV            VG               Attr       LSize    Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  data          pve              twi-aotz-- <337.12g             0.32   0.51                           
  root          pve              -wi-ao----   96.00g                                                   
  swap          pve              -wi-ao----    8.00g                                                   
  vm-100-disk-0 pve              Vwi-aotz--    2.00g data        54.39                                 
  data          pve-OLD-69E16B08 twi-a-tz-- <347.90g             0.00   0.49                           
  root          pve-OLD-69E16B08 -wi-a-----   96.00g                                                   
  swap          pve-OLD-69E16B08 -wi-a-----    8.00g

root@prx:~# cat /etc/pve/storage.cfg
dir: local
        path /var/lib/vz
        content iso,vztmpl,backup

lvmthin: local-lvm
        thinpool data
        vgname pve
        content rootdir,images

@leesteken yes, I think the installer rename it as default behavior, I've installed proxmox only one time whit those disks attached.

 

[leesteken]

@leesteken yes, I think the installer rename it as default behavior, I've installed proxmox only one time whit those disks attached.

Hmm, sdb looks a lot like an old Proxmox installation (because it's almost identical to your current Proxmxo on sda) and not at all like Plex server data, unless you were running Plex inside a VM or container on a Proxmox. Are you sure you have the correct drive installed?

 

[Impact]

The data volume of pve-OLD-69E16B08 is empty and there's no "subvolumes" either so there's no virtual disks you can restore/reuse.
There might be some data in the root volume. You can check with something like this

# To mount
mkdir -p /mnt/pveold
# Writing from memory so this is probably wrong. Use TAB completion to find the right path
mount /dev/mapper/pve-OLD-69E16B08/root /mnt/pveold

# To Investigate
apt install gdu
gdu /mnt/pveold

 

[paranoidnemo]

Hmm, sdb looks a lot like an old Proxmox installation (because it's almost identical to your current Proxmxo on sda) and not at all like Plex server data, unless you were running Plex inside a VM or container on a Proxmox. Are you sure you have the correct drive installed?

Yes, I'm positive, I've detached the disk and directly attached it to proxmox.

 

[paranoidnemo]

The data volume of pve-OLD-69E16B08 is empty and there's no "subvolumes" either so there's no virtual disks you can restore/reuse.
There might be some data in the root volume. You can check with something like this

# To mount
mkdir -p /mnt/pveold
# Writing from memory so this is probably wrong. Use TAB completion to find the right path
mount /dev/mapper/pve-OLD-69E16B08/root /mnt/pveold

# To Investigate
apt install gdu
gdu /mnt/pveold

That's strange tho, you mean that proxmox installer cleaned the disk? It was working just before I powered off the raspberry and attached the SSD to proxmox.
Root is "empty" meaning that there are folders but other than sbin everything is empty.

 

[Impact]

You can see that data has 0.00 Data% and there are no vm- volumes belonging to it either. I can't confidently explain what happened to your data, I can only judge what I see and I see nothing to restore. Maybe you reinstalled on top of the existing PVE disk in which case the data was destroyed but you have backups, right?
The code to rename the VG is here if you want to have a look: https://github.com/proxmox/pve-inst...66266cd7d9a9dc649e2e0/Proxmox/Install.pm#L441
Please don't quote my whole post. It prevents me from editing/fixing issues in the instructions and bloats the thread with redundant text.

 

[paranoidnemo]

Yes I've everything backed up, it's not a big deal. I think I'll proceed to format it and trying to understand how to correctly make it so that I can share it with all my container/vms. Have you a link to the documentation regarding this?

Thanks a lot for the help.