> I believe the ZIL (ZFS intent log) is used to cache during writes, and the L2ARC is used during reads. I think the ZIL (zfs intent log) is an intermediary fo

> I believe the ZIL (ZFS intent log) is used to cache during writes, and the L2ARC is used during reads. I think the ZIL (zfs intent log) is an intermediary for synchronous writes only. My understanding is that it effectively turns the sync write into an async write (from the standpoint of the zpool) -- this is why it requires a faster device than the pool it is used with. If it is absent, the pool itself houses the zil.