For the purposes of this thread, I'm assuming a scenario similar to Fatherland or the Anglo-American Nazi War, in which Nazi Germany dominates Europe, but the rest of the world is free of fascism.
In Nazi Germany and its puppets, Holocaust denial will probably be official policy; during the war the Nazis denied any policy of genocide, and even created a Potemkin village at
Theresienstadt to show the world that no extermination was taking place. Despite the official stance of the Nazi government, knowledge of the killings was widespread throughout the Reich and most of Europe. In a Nazi victory TL, it would be an open secret.
How would the Holocaust be remembered in the rest of the world?
By 1941 Allied governments had fairly detailed knowledge of the camps and the exterminations, and even reports appeared in newspapers in the Allied nations. So I think it's safe to assume that knowledge of the atrocities would be fairly widespread.
However, knowledge alone doesn't mean much. The Armenian, Cambodian and Rwandan genocides are fairly well known, but they have unfortunately had little impact on societies outside the ones in which they occurred. And indeed there would be little more than knowledge. In a Nazi victory there would be few if any survivors, a handful of photos or documents smuggles out of the Reich, and perhaps aerial reconnaissance photos taken by Allied airmen. Without actually seeing the survivors, the corpses, the crematoria and the camps, would the Holocaust still have the same impact on society? With the end of the Final Solution, the camps would be demolished, with only a few artifacts left behind to show what once happened there. The last executioners would die off, and eventually the Reich itself would collapse. The Holocaust would eventually become little more than another name in a litany of past crimes, just another page in the black book of history.
Does this analysis seem sound?