[SOLVED] LVM-Thin Problems

[peanut42]

I have this strangre issue where I can't create VMs with qcow2 disks.

My in place upgrade was a bit botched so I used the opportunity and reinstalled proxmox and set it up with a small LVM-Thin portion as a test. After seeing the default "data" entry in Disks > LVM-Thin, I tried to create VM, but when it comes to the "Hard Disk" options, "Format" was grayed out and locked into raw.

Then, I tried the same Spiel with a separate (from the OS Disk) parition (and disabled data in the UI). This time around I created a Thin LVM via terminal but ended up witthe same result. I see the LVM-Thin entry in UI, but can't create a VM with a qcow2 disk. Any input, thoughts or help is greatly appreciated.



$lsblk
sda 8:0 1 5T 0 disk
├─bcgrp-bcpool_tmeta 253:0 0 80M 0 lvm
│ └─bcgrp-bcpool-tpool 253:6 0 5T 0 lvm
│ ├─bcgrp-bcpool 253:7 0 5T 1 lvm
│ └─bcgrp-bcvol 253:8 0 4.9T 0 lvm
└─bcgrp-bcpool_tdata 253:1 0 5T 0 lvm
└─bcgrp-bcpool-tpool 253:6 0 5T 0 lvm
├─bcgrp-bcpool 253:7 0 5T 1 lvm
└─bcgrp-bcvol 253:8 0 4.9T 0 lvm
sdb 8:16 0 465.8G 0 disk
├─sdb1 8:17 0 1007K 0 part
├─sdb2 8:18 0 512M 0 part
└─sdb3 8:19 0 465.3G 0 part
├─pve-swap 253:2 0 64G 0 lvm [SWAP]
├─pve-root 253:3 0 116.3G 0 lvm /
├─pve-data_tmeta 253:4 0 2.7G 0 lvm
│ └─pve-data 253:9 0 259.7G 0 lvm
└─pve-data_tdata 253:5 0 259.7G 0 lvm
└─pve-data 253:9 0 259.7G 0 lvm

sdb = proxmox
sda = whishful LVM Thin Volume


$cat /etc/pve/storage.cfg
dir: local
path /var/lib/vz
content backup,vztmpl
shared 0

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

lvmthin: becareful-thin
thinpool bcpool
vgname bcgrp
content images,rootdir
nodes xxx


$pveversion
pve-manager/7.0-13/7aa7e488 (running kernel: 5.11.22-5-pve)

 

[danielb]

That's expected. LVM thin predent a raw block device for qemu to use. The CoW features are provided under the hood by LVM thin

 

[peanut42]

That's expected. LVM thin predent a raw block device for qemu to use. The CoW features are provided under the hood by LVM thin

This seems like I am missing something. What other steps do I need to take to make qcow2 possible?

 

[danielb]

You don't. LVM thin provides itself all the features qcow2 would brings. It'd make no sense to use qcow2 on it

 

[peanut42]

You don't. LVM thin provides itself all the features qcow2 would brings. It'd make no sense to use qcow2 on it

Thanks! I should've tried to take a snapshot before opening a new thread.