The wiki page http://wikitech.wikimedia.org/view/Text_storage_data shows the change in the number of text storage objects of each type over the last 18 months. Some of those object types are changing when they shouldn't be. As written in that page, "The rise in "object/historyblobcurstub" doesn't really make sense. The rise in "gzip,external/simple pointer" is concerning."
Find out why they're changing and fix it.