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.)

