When curious about the performance of a server, one of the first places I stop is “top”. Top is not perfect, not by a long shot, but it does provide a decent point in time snapshot of the server, and attempts to answer the question of “what is going on right now?”. Unfortunatly, the output of top can easily be misinterpreted if you do not have a good understanding of the different fields of data presented.
I’m not going to go through the man page for top, when you have the time and inclination it is always there waiting for you. What I would like to do is point out a few highlights of how I use it to get a quick overview of the system and hopefully get a direction I should go next. Top is often my first stop in troubleshooting, but it is rarely my only stop.