But ZIL is a cache, and not usable for long-term storage. If I combine a 1TB SSD with a 1TB HDD, I get 1TB of usable space. In bcachefs, that's 2TB of usable sp

But ZIL is a cache, and not usable for long-term storage. If I combine a 1TB SSD with a 1TB HDD, I get 1TB of usable space. In bcachefs, that's 2TB of usable space. Bcache (not bcachefs) is more equivalent to ZIL.