We don't expose this, but you can find it using lvm.

For example for disk id c5401e6c-9c56-4ddf-b57a-efde3f8b0494

# lvs -o vg_name,lv_name,devices --devicesfile='' --select 'lv_tags = {IU_c5401e6c-9c56-4ddf-b57a-efde3f8b0494}'
  VG                                   LV                                   Devices                                          
  aecec81f-d464-4a35-9a91-6acf2ca4938c dea573e4-734c-405c-9c2c-590dac63122c /dev/mapper/36001405351b21217d814266b5354d710(141)

 

141 is the first extent used by the disk on the device 

/dev/mapper/36001405351b21217d814266b5354d710.

A disk with snapshots can have many logical volumes. Each logical

volume can use one or more luns in the storage domain.

The example works with oVirt 4.5, using lvmdevices. For older versions

using lvm filter you can use:

    --config 'devices { filter = ["|.*|" ] }'

This info is not static, lvm may move data around, so we cannot keep it 

in engine db. Getting the info is pretty cheap, one lvs command can 

return the info for all disks in a storage domain.

Nir