I vaguely recall that the default was to use the current average compression for the default estimation. I always changed it to 1, which is much saner: instead

I vaguely recall that the default was to use the current average compression for the default estimation. I always changed it to 1, which is much saner: instead of being surprised that you didn't have enough disk space to store something, you'd at most get surprised that you had more space left over than you expected after storing something. Even today, things like the transparent compression in btrfs use 1 as the compression ratio for the free space estimate (though its metadata usage can be a bit unpredictable).