This video shows greedy garbage collection on a small SSD and a Zipf random workload. It shows that MinValid converges much slower (compared to the Greedy-Uniform demo) and at a higher value of 15-16 pages. The reason is that cold pages that are rarely updated remain valid during consecutive garbage collection invocations. As a result, write amplification increases, leaving less space available in the erased blocks for invalid copies of hot pages, thus causing even more frequent garbage collection, and so on. This phenomenon is graphically visible as a dense grouping of invalid (X) marks on the plainly filled pages that represent user writes.