Sim já fiz este processo, e para teste removi a VM que estava nesta lun ai ficou só o lixo conforme abaixo, nesta LUNs não existe nenhuma VM:
[root@xenserver01 ~]# for i in `vgs --noheadings -o vg_name`; do vhd-util scan -p -l $i -f 'VHD-*' ; done
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vhd=VHD-2c339b04-fcb4-47a3-b71c-7c91c05ac399 capacity=322122547200 size=8388608 hidden=1 parent=none
vhd=VHD-508fbf32-f823-4d53-acd9-73d1a0cded80 capacity=322122547200 size=322760081408 hidden=0 parent=VHD-2c339b04-fcb4-47a3-b71c-7c91c05ac399
vhd=VHD-d526b673-98b7-430f-9a60-57c806b19a90 capacity=322122547200 size=8388608 hidden=0 parent=VHD-2c339b04-fcb4-47a3-b71c-7c91c05ac399
Se não existe VM e nem Snapshot porque ainda existe dados nela.
[root@xenserver01 ~]# vhd-util scan -f -m "VHD-*" -l VG_XenStorage-8f17afb0-1389-bfc2-ad28-aad2ea6073c5
vhd=VHD-2c339b04-fcb4-47a3-b71c-7c91c05ac399 capacity=322122547200 size=8388608 hidden=1 parent=none
vhd=VHD-508fbf32-f823-4d53-acd9-73d1a0cded80 capacity=322122547200 size=322760081408 hidden=0 parent=VHD-2c339b04-fcb4-47a3-b71c-7c91c05ac399
vhd=VHD-d526b673-98b7-430f-9a60-57c806b19a90 capacity=322122547200 size=8388608 hidden=0 parent=VHD-2c339b04-fcb4-47a3-b71c-7c91c05ac399
vhd=VHD-fc88aee9-ebe0-4210-bde1-bf16d35b423c capacity=322122547200 size=322760081408 hidden=0 parent=none