Since qcow2 only supports metadata preallocation, not full preallocation, I''m wondering if +C on the sparse file is sufficient, or alternatively using qemu-create -o preallocation=metadata,compat=1.1,lazy_refcounts=on? Or is qcow2 on btrfs just not a good idea? Chris Murphy-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html