How to enable DISCARD and WRITEZEROS in virtio-blk in Proxmox 6.0


Well-Known Member
Jul 11, 2018
Hi, I just updated my Proxmox server to 6.0 and I have to say that this update is just amazing.

The version of QEmu got bumped up to 4.0 in this update, which finally brings support for DISCARD and WRITEZEROS to virtio-blk as per QEmu's changelogs ( These features, from what I understand, should help to reclaim free space when used in a thin provisioned volume.

How can I enable this feature on an existing virtio-blk disk in Proxmox? I haven't seen the option in the Proxmox web GUI which makes me think that the feature has not yet been implemented there or I'm missing some preconditions to enable it. If it's not yet supported by Proxmox, is there any way to enable this manually in the configuration files somewhere?

Any hints would be appreciated. :)


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