It's that ZFS is using all the RAM as file system cache to make snapshots and things like that go super-fast. I don't care about how fast my snapshots are, I just want less RAM use and a snappier desktop so I set that set zfs:zfs_arc_max variable to a small amount (like 400 megs or so), way smaller than what the crazy guy in that blog uses.
Keep in mind that this variable is both kernel memory and ZFS file system cache, so don't make it too small. -- This message posted from opensolaris.org
