As heavy users of the LAMP stack for our applications, we of course find that various systems are not performing as expected. We have one webserver (part of an application cluster) that often spikes loads that seem to be unrelated to the actual traffic on the machine. For example, we may have 80 httpd requests, yet the load on the machine is 8 or 9. So- how do we begin to identify where the bottleneck exists? Typically, those bottlenecks can be narrowed to two places- CPU and I/O (disk). We can check our system with a couple of tools to identify where the problem is: vmstat and iostat. Read the rest of this entry »
