That was Toba in Sumatra. I've seen estimates that only 5,000 people worldwide survived this incident.
And that is totally ridiculous. The Krakatoa volcano spewed a dust cloud that lasted for two years. There was no worldwide faunal destruction caused by it. There is no evidence of any species having been affected by this Toba eruption either. Man is far more adaptable than other species so there is absolutely no reason to assume that more humans died as a result of such an eruption than other species unless all of them lived near the volcano which is obviously false. Like the rest of evolutionary theory this is just pseudo-scientific nonsense.