: 1) set dsched_pol_{diskname}="fq" in /boot/loader.conf; e.g. if it : should be enabled for da0, then dsched_pol_da0="fq". You could also : apply the fq policy to all disks of a certain type (dsched_pol_da) or : to all disks (dsched_pol). Note that sernos are not supported (yet).
Beware that I just changed the loader tunables again. They now are kern.dsched.policy.da0, kern.dsched.policy.da and kern.dsched.policy.default respectively. Cheers, Alex