This plugin allows you to send these metrics : number of tests, tests skipped, tests failed, build duration, cobertura total line coverage
and cobertura total branch coverage to one or more graphite servers.
If you don't have a graphite server you can use : https://www.hostedgraphite.com to test.
For cobertura metrics you need to install cobertura plugin and run cobertura:cobertura in goals section.
Be sure to run jenkins your jobs with a Jdk 7 (go to the manage jenkins + configure system + Jdk installations ), because the plugin only works with this version of jdk.