Hi doug
your VM machine need to be switched off to be able to run mbralign
Switch off the VM
run
/opt/netapp/santools/mbralign proliant-000001.vmdk
Then on ESX
To convert to thin again (mbralign do thick only)
vmkfstools -i proliant-000001.vmdk-d thin proliant-000001_temp.vmdk
delete old one
vmkfstools -U proliant-000001.vmdk
rename thin one to original name
vmkfstools -E proliant-000001_temp.vmdk proliant-000001.vmdk
boot your machine
if all good
rm *.vmdk-mbralign-backup
then check your snapshot on the volume as this take a lot of room to do
good luck