I've recently had a bit of a strange problem with my web server. Over the last day or so the site seems to be slowing down somewhat at random intervals, we don't seem to be experiencing any major extra traffic, however a quick look at 'top' and httpd seems to be jumping from between 3-10% to around 99%, then briefly hitting around mid 80's then going back down. For example:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2443 apache 25 0 256m 20m 5472 R 88.2 2.1 3:22.29 httpd
This seems to happen every 30 minutes or so. The strange thing is at the same time this is happening I can run the Apache server-status page and will get (for example):
CPU Usage: u700.5 s6.22 cu0 cs0 - 20.2% CPU load
So my question is two-fold:
- Does anyone know why this issue may have cropped up over the last day or so (there have been no changes made to the server)
- Why would my CPU usage stats in top be vastly higher than server-status and which is correct?