Originally Posted by Vot
Versioning or journaling or both?
Good question. Or perhaps N/A.
The short answer is not journaling.
The slightly longer answer is that I hope it shakes out to be a bit like FreeBSD UFS(?) in that you use ordered writes and have no need for journaling. Hopefully a greedy allocator requiring more space than "optimal" can give some guarantees so you don't get too many corner cases that suddenly breaks down the promised operation.
That is an interesting thing to find out.