[pve-devel] qcow2 on block devices

[Dietmar Maurer]

> Subject: Re: qcow2 on block devices
> 
> I don't understand, what does it do ?

It formats an LVM volume with qcow2. So you can basically use an
lvm volume and create snapshots on it.

somehow cool - but I am not sure if its usable. 
How much free space should we provide?

> 
> ----- Mail original -----
> 
> De: "Dietmar Maurer" <dietmar at proxmox.com>
> À: "Alexandre DERUMIER (aderumier at odiso.com)"
> <aderumier at odiso.com>, pve-devel at pve.proxmox.com
> Envoyé: Vendredi 24 Août 2012 12:09:00
> Objet: qcow2 on block devices
> 
> 
> 
> Wow, just detected a new feature ;-)
> 
> # qemu-img info /dev/pve/vm-100-disk-1
> image: /dev/pve/vm-100-disk-1
> file format: raw
> virtual size: 1.0G (1073741824 bytes)
> disk size: 0
> 
> # qemu-img create -f qcow2 /dev/pve/vm-100-disk-1 1G Formatting
> '/dev/pve/vm-100-disk-1', fmt=qcow2 size=1073741824 encryption=off
> cluster_size=65536
> 
> # qemu-img info /dev/pve/vm-100-disk-1
> image: /dev/pve/vm-100-disk-1
> file format: qcow2
> virtual size: 1.0G (1073741824 bytes)
> disk size: 0
> cluster_size: 65536
> 
> # stat -L /dev/pve/vm-100-disk-1
> File: `/dev/pve/vm-100-disk-1'
> Size: 0 Blocks: 0 IO Block: 4096 block special file
> 
> 
> So how can we use that?