I'm using Proxmox Virtual Environment to run few virtual machines. I use raw storage format and I need that the disk is fully pre allocated when created so it does not grow.

The proxmox says that this is default behavior but I experience the opposite. New virtual machines don't take any disk space and they grow up eating whole physical disk. This takes down all virtual machines at once with fatal disk failure.

I found this thread and put some posts: https://forum.proxmox.com/threads/disabling-thin-provisioning.20226/#post-103097 but there's no reply so far.

I would appreciate any help, even if it would work for creating new VMs only.


This depends on the underlying storage type where you save the (raw) image file.

I just tried on my setup. (PVE 4.4)

  1. create (KVM) VM with 5 GB virtual HDD on a local ext4 filesystem on the host using raw format.
  2. -rw-r----- 1 root root 5.0G Jul 12 11:52 vm-190-disk-1.raw

My guess is that you use LVM-thin or ZFS storage and they default to thin provisioning.

  • I use LUKS encrypted NFS4 on LVM, would you know how to configure it ? – Pavel Niedoba Sep 1 '18 at 17:35
  • I still don't have solution to it other than observe free space carefully. – Pavel Niedoba May 12 '20 at 13:54

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