VMware Thick to Thin: Converting Disk Provisioning

New VMware virtual disks default to thick provisioning, and converting an existing disk to thin afterward isn’t a checkbox in the vSphere Client — how you do it depends on whether you’re on the paid vCenter-managed version or standalone free ESXi.

With vCenter (Paid, Multiple Hosts)

Perform a Storage vMotion and select a thin-provisioned format for the destination disk — this migrates the VM’s storage live and converts the provisioning type as part of the move.

With Standalone Free ESXi (No vCenter)

1. Power off the VM you want to convert.
2. Enable SSH: Host > Manage > Services > TSM-SSH > Start.
3. SSH into the host (PuTTY or any SSH client works).
4. Navigate to the VM’s folder:

   cd /vmfs/volumes/<datastore>/<vm-folder>

5. Clone the disk to a thin-provisioned copy:

   vmkfstools -i vm01.vmdk -d thin thin-vm01.vmdk

Once the clone completes, edit the VM’s settings to point at the new thin-provisioned VMDK in place of the original, power it back on, and confirm in the VM’s disk properties that it now shows as thin provisioned. This approach works across ESXi versions, not just the one it was originally tested on.

Broadcom Brought Free ESXi Back (Updated for 2026)

Broadcom discontinued the free standalone ESXi tier in February 2024 after acquiring VMware, then quietly reinstated it in April 2025 bundled with ESXi 8.0 Update 3e — as of 2026 it’s downloadable again from the Broadcom Support Portal with a free account. The restored free tier is standalone-only (it still can’t connect to vCenter), capped at 2 physical CPUs per host and 8 vCPUs per VM, comes with no official Broadcom support, and drops vMotion/DRS/HA/VADP-based backups — positioned squarely for home labs and dev/test rather than production. The good news for this specific process: Broadcom’s own current documentation confirms the vmkfstools -i -d thin SSH-based cloning approach above still works identically on ESXi 8.x and 9.x, on both free and licensed hosts, since it’s a filesystem-level datastore operation independent of licensing tier.

Resources

• Virtual Machines
• vSphere
• VMWare
• PuTTy
• vmkfstools
• virtual machine