This article is an extension of the previous article about storing sessions in Memcached with PHP. Using Memcached for sessions storage is generally a matter of speed (storing them in memory is faster than on disk) and of scalability (using a Memcached server allows you to have several web servers serving the same PHP application […]
Sometimes you find a perl in some code and it might take you a while to understand. In the sessions management code of Chamilo, I found this the other day, then decided to leave it for later because I was in a hurry. Then today, I found it again, and again… it took me about […]
Working with Git is… complex. It’s not that it’s from another world, and the complexity is probably worth it considering the crazy things it allows you to do, but sometimes it’s just mind-bloggingly complex to understand how to do things right. Recently, we’ve had to manage a series of projects with changes that cannot be […]
While reading about Doctrine’s cache mechanism (which applies to other stuff than database queries, by the way), my eye was caught by a little message at the end (last section) about cache slams. I have used cache mechanisms extensively over the last few years, but (maybe luckily) never happened to witness a “cache slam”. There’s […]
If you’re like me and you’ve developed a CDN distribution for your website’s content (while waiting for SPDY to be widely adopted and available in mainstream distributions), you might have noted that the Googlebot is frequently scanning your CDNs, and this might have made your website a bit overloaded. After all, the goal of the […]
I don’t know about you, but in the latest months, I’ve received a series of requests which follow the same pattern: LINK REMOVAL REQUEST Dear Website Owner: It has come to our attention that a number of links exist on your domain which send traffic to our website [theirdomain.com]. We have determined that these links […]
This article is co-authored by Jérôme Warnier, from work mostly done by him with my occasional support. Kudos go to him. We couldn’t find any valuable manual to install Redmine 2.1 on Debian Squeeze, and we sure met a lot of resistance along the way, so we came up with the following step-by-step guide… Sources […]
This is the life-saver cheatsheet you need if you’re ever going to want to understand complex rewrite rules like the ones generated by the Boost module in Drupal: http://www.askapache.com/htaccess/mod_rewrite-variables-cheatsheet.html In particular, in RewriteRule .* – [S=5], the [S=5] rule means “skip the next 5 lines”. It can represent a considerable efficiency boost! Same thing can […]
Munin 2.0 has been released and packaged for Debian, and even backported to Squeeze (from backports.debian.org). Even though there are still some quirks in this version (or just the Debian packaging), it is far better (more scalable, more powerful and prettier) than version 1.4. Basically, the following article should cover it all: http://munin-monitoring.org/wiki/CgiHowto2, but doesn’t […]
If you ever face an optimization issue in MySQL or MariaDB and want to know how to measure/benchmark the differences in execution between two queries, you should definitely know about the set profiling=1; command. Here is how it works: mysql> set profiling=1; Query OK, 0 rows affected (0.00 sec) mysql> SELECT count(login_user_id) FROM stats.track_e_online WHERE […]
We are currently trying out this Fail2Ban rule on one of our server, to block simple (but very upsetting) DOS attacks on Nginx automatically (after 30 seconds). New filter in /etc/fail2ban/filter.d/nginx-dos.conf: # Fail2Ban configuration file # # Generated on Fri Jun 08 12:09:15 EST 2012 by BeezNest # # Author: Yannick Warnier # # $Revision: […]
In Drupal 7, there is a *very tricky* problem you might fall upon at some point. We did and because it’s not *really* a Drupal bug (although it could be considered as a usability bug), it’s worth writing down. The problem is simple: one admin (Joe) and two editors (Sam and Max) edit a website. […]
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