MK Livestatus - a Nagios event broker module that allows quick,
direct and comfortable access to your status data.

Livestatus is concepted and tuned to reduce disk, memory and cpu loads
caused by live-data processing on the Nagios system. Just as NDO,
Livestatus makes use of the Nagios Event Broker API and loads a binary
module into the Nagios process. But other than NDO, Livestatus does not
actively write out data e.g. to the disk. Instead, it opens a socket for
external applications to connect to and fetch the current status
information from Nagios.

WWW: http://mathias-kettner.de/checkmk_livestatus.html