dimitris kalamaras

math, social network analysis, web dev, free software…

Month: July 2014

Magnified reality

Here’s a series of 31 images taken with a Dino-Lite digital microscope. I won’t go in details about the original source of the images, since most of them are pretty obvious (i guess).
Some of them are of poor quality, due to trembling hand or low resolution of Kamoso (KDE’s picture retriever). Anyway, have fun…

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Varnish Cache How-To: Intro to High-Availability for Drupal lovers (and WordPress addicts)

Varnish (openclipart)

What is Varnish?

Varnish Cache or just Varnish is an open-source HTTP accelerator and caching reverse proxy for web servers, like Apache or nginx, hosting content-heavy dynamic web sites.  In non-geek speak, Varnish is an free program which runs in front of your web server (which in this context is called backend or origin) and stores (caches) a copy of each webpage served by the web server.  When a user requests a cached page, Varnish steps in and serves the cached copy instead of requesting the same page again and again from the backend server. So Varnish is ideal for developers who run high traffic sites with lots of visitors and like their web application to be highly available and running fast. This how-to is an attempt to present a comprehensive but simple introductory guide to Varnish configuration for web developers who want to scale their projects gracefully.

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