They're not quite append only, there's a ‘zone random write area’ that you can update in-place that exposes the write buffer in front of a zone. To a lesser deg

They're not quite append only, there's a ‘zone random write area’ that you can update in-place that exposes the write buffer in front of a zone. To a lesser degree, it also supports parallel appends, which naturally aren't purely sequential either. So you've got random writes both between zones and at the front of each zone. The one thing missing is being able to erase blocks within the committed portion of a zone, but idk how you'd support that without just reimplementing a block layer.