  In the year 2011, the CMS collaboration introduced the novel concept of data
scouting, allowing to take data that otherwise would be rejected by the usual
trigger filters. This special data flow, based on event-size reduction, was
created to maintain sensitivity to new light resonances decaying to jets or
muons, with very small online and offline resources allocated to it. The
challenges implied by this new workflow and the solutions developed within the
CMS experiment are shown. This technique is now a standard ingredient for CMS
data-taking strategy. The present status of data scouting in CMS is presented.

High Energy Physics - Experiment