Performance data of nagios


iam using nagios 2.8 in fedora core 6.i want nagios to monitor performance data of the system.kindly help me telling that what are the plugins we have to configure in order to get the performance data.i also want to store the performance data obtained from nagios in a mysql database.kindly specify me the necessary plugins which i have to use in order to connect nagios and mysql database so that monitored performance data from nagios is stored in mysql.kindly specify me the name of the would be too helpful if you can provide me a screenshot or a image showing how the performance data obtained from nagios would look like.even if there is any site specifying how the performance data would look like kindly specify me the link.also specify me what other plugins i have to use so as to obtain the complete monitored details from nagios.also help me telling whether are there plugins already available for my above mentioned tasks or is it my role to write the plugins.if we have to compulsarily write our own plugins in case there is no existing plugins for my above specified needs then kindly help me with the procedure for writing our own plugins.if there is any site specifying the procedure to write our own plugins kindly mention the link.i would be too helpful if you are clearly guiding me on what is a performance data and how it would look like.