Thin Provisioning (Sparse) Volume


Renowned Member
Apr 22, 2015

Out of the box on Proxmox 5.x installs, the RPOOL volume is enabled with thin provisioning.

Specific application:

I use NFS volumes as export shares from the RPOOL. So, for example I share out /var/lib/vz which is part of the rpool. My nodes can then create VMS in that storage pool and their disks are automatically thin provisioned.


If I create additional datapools on a PMX 5.x server, those pools are not thin-provisioned. Disks take up all of the space that they are allocated. Further, even if I use the Proxmox GUI and select Thin Provisioning as a feature for Local ZFS storage, the VM disks are not thin provisioned.

Any ideas on what needs to be done to create the datapool so that its files are thin provisioned like the rpool?

Additional info:

The rpools in my other servers are SATA disks.

This particular datapool is a mirror of two Intel 480GB SSDs.
I just attempted the experiment on another Proxmox host to confirm. If I create a new zpool with the command:

zpool create POOL_NAME mirror drive1 drive 2

The new pool uses up all 70GB for a lightly used disk on a CENTOS VM. In proxmox, I have selected thin provisioning and moved the disk to that pool.

However, just like before if I move the disk to the rpool, the file is then thin provisioned.

This is even true if moved to local storage on the rpool.

What do I need to do when creating new datapools so that they will be thin provisioned just like the rpool?
Does anyone know how to create an additional zpool that is thin provisioned?

What do you mean by thin provisioned a zpool? The PVE GUI setting does not set the quota on the created filesystems if thin provisioning is enabled. This is the normal behaviour for ZFS filesystems. For ZFS volumes, however, this setting also implies the spare setting (-s), which is not a default one.


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