I would expect ZFS to outperform btrfs because of ARC and ZIL. ARC allows ZFS to increase the cache hit rate. ZIL permits ZFS to update its on-disk trees asynch

I would expect ZFS to outperform btrfs because of ARC and ZIL. ARC allows ZFS to increase the cache hit rate. ZIL permits ZFS to update its on-disk trees asynchronously. I am not aware of any analog to this in btrfs. Desktop users typically report that their systems become more responsive after switching to ZFS. The only case where I suspect btrfs might significantly outperform ZFS involves getdents() when the caches is cold. This is because ZoL does not presently do readahead on directory lookups. This has a noticeable impact on the performance of `ls` on the first access of a directory on mechanical storage, but it is not a problem for subsequent reads or on solid state storage. Prefetch support in getdents() will likely be implemented in either the next release or the one that follows.