check_bioctl (Visit this link)

The only real caveat with it is that bioctl needs rw permission to
/dev/bio. One way to allow for that is by adding an entry to
/etc/sudoers and then making the check run sudo check_bioctl.

This is an example of a setup for NRPE. For checks on the machine running
Nagios, use the _nagios user in /etc/sudoers instead of _nrpe, and of course,
no /etc/nrpe.cfg.

/etc/sudoers:
_nrpe ALL = NOPASSWD:${PREFIX}/nagios/check_bioctl -d ami0

/etc/nrpe.cfg:
command[check_bioctl]=/usr/bin/sudo ${PREFIX}/nagios/check_bioctl -d ami0

For more information on bioctl(8) see the OpenBSD man page.

http://www.openbsd.org

v1.16 now obeys the check timeout value from utils.pm