Home / server / Questions / 351448
Accepted
Matt
Asked: 2012-01-20 03:49:01 +0800 CST

Our web server grinds to a halt when making XMLRPC requests. Please analyse my `top` output to see what's wrong

  • 772

This a shared web server for our office and normally runs just fine with a few devs working on it simultaneously.

However, I've recently started working with it using Wordpress and it's XMLRPC API feature and things turned sour. I'm making an iPhone app that requests data from the API, the responses of which are around 5k-8k in size.

The server ends up in the state shown below after sending one batch of API requests. After a few minutes it returns to normal with load averages of, right now, 0.08, 0.81, 0.93

top

Can anyone diagnose this? I have no clue how to interpret all the columns. Any help would be much appreciated.

linux centos apache-2.2 top

1 Answers

  1. Best Answer

    In the info you posted your problem is that you are running out of memory and so your server starts to swap, a lot. Swapping is extremely slow, so all your applications end up slowing down. You can see this where it says 6124k free in the memory row, and 531316k used in the swap row. Having a low mem free number is fairly common, so you also have to look at 13284k cached number, which is how much of your memory is used for caching, which is also pretty low, meaning most of your ram is in use by programs. What those programs are is hard to tell as your screenshot does not show this information (posting ps aux output would be much better here). However in top, you can press SHIFT+M to sort by memory usage.

    • 4