Many people with ZFS experience have probably heard that ZFS is designedto work safely with disks with write caches, and may also have heardthat this is done with cache flush commands. The details of what getdone when and under what circumstances are a bit complicated, though.

First, I'm only talking about the situation where you give ZFS wholedisks, instead of slices. When you do this, ZFS marks the device asbeing a whole disk in the pool configuration, and the remaining magic isdriven from