We should switch to native Python operations wherever feasible, but I can't see the problem you're describing. I've tested the sparseness at every stage and while ls shows a 4GB image, du consistently shows it occupying 300M on disk. What are you seeing that suggests this is not sparse?
We should switch to native Python operations wherever feasible, but I can't see the problem you're describing. I've tested the sparseness at every stage and while ls shows a 4GB image, du consistently shows it occupying 300M on disk. What are you seeing that suggests this is not sparse?