On Tue, 2018-02-06 at 15:31 +0100, Thomas Güttler wrote: > .... But one thing is still unclear. Imagine I see a peak in the chart. The peak > was some hours ago. AFAIK sar has only the aggregated numbers. > > But I need to know details if I want to answer the question "Why?". The peak > has gone and ps/top/iotop don't help me anymore. >
The typical solution is to store stats on everything you can think of with munin, cacti, ganglia, or similar systems. I know with ganglia at least, in addition to all the many details it already tracks on a system and the many plugins already available for it, you can write your own plugins or simple agents, so you can keep stats on anything you can code around. Munin's probably the easiest to try out, though.
