One can then use local disk as a ZIL to improve IOps. When "Hybrid Storage Pools" storage pools were first introduced in 2008, when flash was still really expe

One can then use local disk as a ZIL to improve IOps. When "Hybrid Storage Pools" storage pools were first introduced in 2008, when flash was still really expensive, this was a clever way of balancing speed and bulk storage with budget constraints: * https://ahl.dtrace.org/2008/11/10/hybrid-storage-pools-in-the-7410/ https://ahl.dtrace.org/2008/11/10/hybrid-storage-pools-in-th... Nowadays flash is cheap/er, so all-flash storage is much more popular, with many storage products able to do tiered storage where (c)older data bits are shuffled from fast-expensive flash to slow-cheaper spinning rust.