You can use iostat(8) if you're trying to ascertain the "transfer rate" the of drive... are you?
$ iostat -d wd0 cd0 cd1 fd0 KB/t t/s MB/s KB/t t/s MB/s KB/t t/s MB/s KB/t t/s MB/s 18.10 1 0.03 0.00 0 0.00 0.00 0 0.00 3.88 0 0.00 $ Beware though, for months I thought OpenBSD couldn't achieve more then 1MB/s write speeds... Then I enabled write cache with atactl(8) and everything was fine... (Shame on me..) -Nix Fan. (Apologies for the CC, Not sure if you're subscribed.)