zfs and vfs.zfs.prefetch_disable="1"

[Randy Bush]

i have in my incantations for zfs on i386 to stick the following in
/boot/loader.conf.local

vm.kmem_size=600M
vm.kmem_size_max=600M
zfs_load=YES
vfs.zfs.prefetch_disable=1

but i have no idea where that last one crept in.  any clues?

randy