Inflating the vmdk fails with the error "cannot be inflated because it is not a vmfs thin-provisioned disk"

Products

• VMware vSphere ESXi

Issue/Introduction

Converting Thin disk (Full utilized) to Thick disk when there is no access to the vCenter.

Symptoms:
vCenter / Storage vMotion unavailable.
Size of virtual disk shows as full within the datastore.
Disk is thin provisioned.
Inflating using the ESXI Host UI the operation fails wtith the error "cannot be inflated because it is not a vmfs thin-provisioned disk"

In hostd.log file, you see entries similar to : 

Hostd.log 
==========================
2023-05-19T07:56:43.278Z warning hostd[2100372] [Originator@6876 sub=Vdisksvc opID=esxui-b65c-08d3 user=root] The virtual disk (/vmfs/volumes/6177bdb6-17f9f458-83b3-d4f5ef5b21b0/Mng-Zabbix/Mng-Zabbix.vmdk) cannot be inflated because it is not a vmfs thin-provisioned disk - type: <11>, capacity: <322122547200>, used: <322122547200>.

Environment

VMware vSphere ESXi 7.x

Cause

• This is not a defect or a bug as the code defined is working as expected.
• Inflate works on converting Thin to Thick disk by following the method of eager zero (Process to format the disk by writing them with zeros prior to writing any Data)
• Inflate considers the parameters "capacity" & "space Used" for the VMDK at the time of execution.                                                 Eg : capacity: <322122547200> == spaceUsed: <322122547200>
• Inflating the VMDK, with no space left on the virtual disk itself,  will fail leading to the error as there is nothing to zero out.

Resolution

You can follow either of the 2 process listed below :

Resize the Virtual Disk 

1. Access the ESXI Host UI.
2. Right-click the virtual machine.
3. Click Edit Settings.
4. Select Virtual Disk.
5. Increase the size of the disk.

Note: If this option is greyed out, the disk may be running on snapshots or the disk may be at the maximum allowed size depending on the block size of the datastore.

Clone the disk using the vmkfstools

See :
Cloning and converting virtual machine disks with vmkfstools (1028042)
https://kb.vmware.com/s/article/1028042

Workaround:
N/A

Additional Information

Cloning and converting virtual machine disks with vmkfstools (1028042)

https://kb.vmware.com/s/article/1028042