How many people were affected during the famine? Are there any sources for Soviet records on the Holodomor?
According to the official internal Soviet statistics, the number of excessive mortality in Ukraine in 1932-1933 was 1,532,700 people, of which 1 million 385 thousand in 1933.
A paradoxical fact of this is that in 1933 the total harvest for the USSR was 69 million tonnes (some think this number is overestimation due to the counting method used in the USSR and the actual harvest was about 50 million tonnes), compared to average 35 million tonnes during the war, which did not cause a hunger. The shipment of grain abroad was also drastically cut in 1933. The harvest of fish in 1933 was also very good.
From 19 March 1932 to 4 July 1933 the government shipped additional 1 million tonnes of food to Ukraine at expense of other regions.
It should be noted also that the most of deaths happened in June and July of 1933, during the summer, an non-typical time for hunger.
Another peculiarity of the deaths was that there were no reports of dystrophy which is typical for any historical hunger, including that of 1920s in Volga region, of 1947 and of the siege of Leningrad, as well as hungers in India. Instead, there were numerous reports of widespread tumescence.
It was conjectured by some historians that the actual reason for the excess deaths was a liver disease due to consumption of defective grain.
This could happen because a serious portion of grain was hidden from the state agents or stolen from the kolkhoz fields. The farmers could not purify and winnower their grain themselves because the necessary equipment was transferred to the kolkhozes in the course of collectivization.
It is known that consumption of such grain leads to exactly the same symptoms as those reported for the victims.
Also there were no reported cases of mortality in cities, which always consumed properly processed grain.
Kosior in his report to Stalin wrote:
Why they starve in Kiev oblast where we did virtually no grain procurements?
Overall the picture was the same: where the less were procurements, the higher was mortality.
It should be noted also that there were reported numerous cases where grain storages were found in households where all the family members were found dead.
Kosior wrote to Stalin:
There are facts that many kolkhoz and individual farmers under the influence of panic have hidden their grain, but at the same time they starve themselves. Only in Dnepropetrovsk oblast there were uncovered over 50 such cases.
According to one GPU repot,
At the household of kolkhoz woman Yurchenkova who reported that she was tumescending due to hunger it was discovered 8 poods of rye.
Given these reports and the harvest statistics (which was known to Stalin) it is possible to suggest that Stalin possibly thought that there was enough food available and the farmers intentionally had hidden it and starved due to their own greed.
The Western authorities on this are Robert Conquest (Harvest of Sorrow) and Timothy Snyder, already mentioned. Robert Conquest gives an estimate of 4 millions. Snyder is somewhat more conservative.
But we will never know the exact number: the earliest census after this was forged, and those who did it exterminated.
EDIT. In one comment a method of "asking random Ukrainians" is proposed. I am a Ukrainian, and my grandparents survived it, by escaping from a village to a large city (Kharkiv) shortly before it began. I lived in Ukraine for 36 years, and have heard plenty of eyewitness accounts.
From Wikipedia: http://en.wikipedia.org/wiki/Holodomor#Death_toll
A 2002 study by Vallin et al. utilizing some similar primary sources to Kulchytsky, and performing an analysis with more sophisticated demographic tools with forward projection of expected growth from the 1926 census and backward projection from the 1939 census estimate the amount of direct deaths for 1933 as 2.582 million. This number of deaths does not reflect the total demographic loss for Ukraine from these events as the fall of the birth rate during crisis and the out-migration contribute to the latter as well. The total population shortfall from the expected value between 1926 and 1939 estimated by Vallin amounted to 4.566 million. Of this number, 1.057 million is attributed to birth deficit, 930,000 to forced out-migration, and 2.582 million to the combination of excess mortality and voluntary out-migration.
According to historian Timothy Snyder, the recorded figure of excess deaths was 2.4 million. However, Snyder claims that this figure is "substantially low" due to many deaths going unrecorded. Snyder states that demographic calculations carried out by the Ukrainian government provide a figure of 3.89 million dead, and opined that the actual figure is likely between these two figures, approximately 3.3 million deaths to starvation and disease related to the starvation in Ukraine from 1932–1933. Snyder also estimates that of the million people who died in Soviet Russia from famine at the same time, approximately 200,000 were ethnic Ukrainians due to Ukrainian-inhabited regions being particularly hard hit in Russia.
According to the Encyclopædia Britannica, the overall number of Ukrainians who died from 1932–1933 famine is estimated as about four to five million out of six to eight million people who died in the Soviet Union as a whole.
There was more than one Holodomor genocide in 20th century Ukraine. At least three major famine-genocides occurred: 1921-23, 1932-33, 1946-47.
(Sorry, didn't find English sources)
The area which suffered most (per capita) from that famine was Northern Kazakhstan; Lower Volga region numbers are lower but comparable to Ukraine. Those dastardly Soviet rulers, it seems, "conspired" to exterminate mostly Russian population of Northern Kazakhstan and Lower Volga... but perhaps they were only doing that to distract the world from their real purpose, to kill all the Ukrainians, so that nobody would notice? There is really no logical explanation for this fictional "intentional Holodomor genocide" unless you believe the (ridiculous on its face) idea that Soviet rulers had deep and villainous hatred of specifically Ukrainians ... why Ukrainians and not Tatars or Cossacks or Armenians? They must have tossed a coin, I guess.
The most logical (if you discount theories based almost purely on propaganda) explanation is that some (quite moderate) "natural" drought/famine was very much exacerbated by Stalinist policy of forced collectivization and also by the grain confiscation policies executed in 1929 and before, which among other things led to lack of seeding material. One of the semi-logical reasons was that USSR was desperately in need of hard currency for the rapid rebuilding of its industry and trying to level the military and industrial field (considering the prolonged "cold" and sometimes not very cold war Europe and USA still conducted vs USSR). So they did that by selling off whatever they had - art from museums, gold confiscated from churches, grains from the fields. Quite a debatable solution, to say the least, but that's what they did.
Added (hopefuly this will add some basis/sources/etc). R. W. Davies, Stephen G. Wheatcroft - The Years of Hunger. Soviet Agriculture, 1931-1933 (Industrialization of Soviet Russia) (Vol 5), Palgrave Macmillan (2004)
Can be downloaded via Library Genesis. It contains a very detailed econo- and socio-analysis of the famine. E.g., table 48, p.511 has death rates for Volga region and Ukraine.