There is something broken with caching for the productfooter module. In “cache/smarty/cache/footerproduct” there is a folder for every product of the eshop, I think this is not how it should work. Every folder has around 10 subfolders. Check it. Deleting it takes hours.

Also, before update, 700mb was enough for my eshop. Now it has 1.7GB, there must be some serious bug.