Jetty Timeout Problem When Serving Images

Hi,

I’m running a Spring MVC app served by an embedded Jetty server on Ubuntu 14.04. I also have a MySql server running. I have added swap space to prevent out-of-memory errors according to this tutorial: https://www.digitalocean.com/community/tutorials/how-to-add-swap-on-ubuntu-14-04

The droplet is the 5 USD/mo one with 512MB RAM, 1 core, 20 GB SSD. Performance is actually quite nice overall, but looking at the logs there are some hickups occasionally:

java.io.IOException: java.util.concurrent.TimeoutException: Idle timeout expired: 300000/300000 ms

This exception is only thrown for images; such as “images/lowres/a.jpg”, “images/lowres/b.jpg” and so on.

This error occurs almost exclusively on a page which serves 15 images, each of size about 35KB, so roughly 0.5MB.

What happens is that either all images load nicely in about 700-900 ms or 1-5 images are not loading, and these then proceed to time out, thus throwing the above IOException after 300000 ms (5 mintues).

I want to understand what is happening here, and how to fix it. Feedback is very much appreciated!

Just realized it would be a good idea to monitor the memory usage of my droplet to see if this is possibly a memory issue

Thanks!