Alvy most likely derives from the Irish name Ailhbe, also spelled Ailbe. Consider this from a Celtic name list:
So my translation of Alvy as white (see my chop) is somewhat justified. The first Alvy Ray Smith, my grandfather, married a very Irish woman, Sina Maudie McKindrey, so I am clearly part Irish (Northern Irish, if that distinction is important to you). I believe my grandpaternal line is also Irish but have no proof.