Logon to the ESXI Server where the VM is stored using a product like putty.
The following command lists the datastores:
ls/vmfs/volumes
ls /vmfs/volumes/ESX01_Internal1/
ls /vmfs/volumes/ESX01_Internal1/RDS2012/
ls vmfstools -k /vmfs/volumes/ESX01_Internal1/RDS2012/RDS2012.vmdk
Use “vmfstools -k” to convert a Lazy Zeroed disk to a Eagerly Zeroed disk.