DTrace (or other monitor) access to LBA of a block device

[Thomas Zander]

Hi,

do we have any way to monitor which LBAs of which block device are
read/written at a given time?

I stumbled upon this,
http://southbrain.com/south/2008/02/fun-with-dtrace-and-zfs-mirror.html

which is pretty intriguing. Unfortunately on FreeBSD we do not have
the DTrace io provider, so his dtrace script would not work.
Do we have another option to monitor block device access in a similar fashion?

Regards,
Riggs