From the document explanation below, the formula is "Logical Used Size = Used Size + Space Saved by Storage Efficiency" -logical-used This value includes all the space saved by the storage efficiency ...From the document explanation below, the formula is "Logical Used Size = Used Size + Space Saved by Storage Efficiency" -logical-used This value includes all the space saved by the storage efficiency features along with the physically used space.This does not include Snapshot reserve but does consider Snapshot spill. ::> volume show -vserver <> -volume <> -instance Used Size: 5.43TB Total Physical Used Size: 5.72TB Logical Used Size: 5.49TB Logical Size Used by Active Filesystem: 4.37TB