Symptoms
When you expand an Eager zero thick provisioned disk it changes to Lazy zero thick provisioning disk.
Cause
This issue occurs when the default Thick Provision Eager Zeroed is created the data remaining on the physical device is zeroed out when the virtual disk is created, when you expand the disk it will not zero out the blocks from the storage array this changes the eager zeroed disk to lazy zeroed thick provisioned disk.
Resolution
Zero the disk again:vmkfstools --eagerzero /vmfs/volumes/myVMFS/VMName/disk.vmdkhttps://docs.vmware.com/en/VMware-vSphere/6.7/com.vmware.vsphere.storage.doc/GUID-60B9C89A-6638-43FA-A8E3-4DACAC85FC29.htmlAnother option is to do a storage vMotion of the affected disk and it will change back to Eager Zeroed disk again.
