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Posts tagged Information Technologies
The importance of a good system monitoring
994 days
Servers are the keystones of any organisation working with computers, and to ensure productivity, you must make sure there will be the fewest downtimes possible. To have a correct Level of service, one of the first things to do is to elaborate a monitoring plan.
Why server monitoring has to be performed?
This question might sound ridiculous, but it’s important to know the reasons why you should monitor your servers.
First, if you have plans for the future, then you must monitor your servers, monitoring will allow you to know how the present is and where to go.
- Disk Usage: How is you space used and how is it growing over time?
- Memory usage: How is your system memory used? Do you plan to have more users in the future?
- CPU usage: Will you need to upgrade the number of processors installed on the server if your number of users increases?
Monitoring will also allow you to prevent incidents, or at least identify them before your customers do. If you know how is going your server, you might notice a possible failure and take actions before it (for ex: /var nearly full, one of your process is going crazy, etc…). (more…)
Why stress testing applications ?
999 days
Stress testing is one of the most important part of development lifecycle as computers have taken a big part in our working life. Everybody working in an office is using a computer, and with that, software installed on it or shared over a network. Applications are probably going to be used by more than one person at a time and you must make sure that, whatever the number of users you have, the application will keep on working in an acceptable way.
We can define software in three categories, local, remote and web applications. (more…)
[Linux] Lighttpd webserver
1387 days
In the world of open source web servers, you mostly talk about Apache, but the problem with Apache is that for development, it’s quite heavy and slower than other alternatives, such as Lighttpd. Even if in Lighttpd there is the word light, it doesn’t mean that it comes with fewer features. In fact, it’s far from the truth as light only stands for the small memory footprint and speed for static page serving.
Here is a list of some features available with Lighttpd :
Virtual hosts
Virtual directory listings
URL-Rewriting, HTTP-Redirects
Large File Support (64bit fileoffsets)
on-the-fly output-compression with transparent caching
deflate, gzip, bzip2
authentication : basic, digest
backends: plain files, htpasswd, htdigest, ldap
fast and secure application controlled downloads
Server Side Includes
User Tracking
FastCGI, CGI, SSI
Same speed as or faster than apache + mod_php4
Includes a utility to spawn FastCGI processes (neccesary for PHP 4.3.x) via FastCGI and CGI interface
load-balanced FastCGI (one webserver distibutes request to multiple PHP-servers via FastCGI)
chroot(), set UID, set GID
protecting docroot
strict HTTP-header parsing
Pure happiness for sysadmins and web developers. Lots of websites are already using it in a way or another, like YouTube, Wikipedia or even sourceforge.net.
Enough with the talk, let’s move to the installation, I’ll talk of the installation under Ubuntu, which is one of the most popular GNU/Linux distribution, and also the one that I personally use.
The first step is to install the packages using the apt-get command :
sudo apt-get install lighttpd lighttpd-doc libpcre3
Here you are, with your brand new Lighttpd installed. If with that installation you need to use mysql and php, you have to install these packages : mysql-common, libmysqlclient12, php5-cgi and even mysql-server if you need to host the database on the same server
In case you want to use php5, you need to activate the fastCGI module by issuing the following commands in a terminal:
sudo ln -s /etc/lighttpd/conf-available/10-fastcgi.conf /etc/lighttpd/conf-enabled/10-fastcgi.conf sudo /etc/init.d/lighttpd restart
Here you go, you have your lighttpd installed with php5 alongside.
Now, all you have remaining to do is to change your settings according to your needs. To do so, my advice would be to browse the official documentation here. Or even better, ask me in the comments here and I’ll try to answer as soon as possible.
Gérer le volume par application sous Linux
1399 days
Traduction de l’article de Tombuntu:
PulseAudio est un nouveau serveur de son qui sera inclus dans Ubuntu 8.04 ainsi que dans les distribution récentes. Généralement, un serveur de son permet de changer le volume de manière globale. Pulse audio permet quand à lui de gérer le volume directement par application si vous le désirez, il possède aussi une architecture par plugins, une latence faible et des capacités réseaux.
PulseAudio permet de faire beaucoup de choses, mais une des fonctionalitées les plus interessante est de permettre de gérer le volume des applications individuellement. Ce qui est pratique pour des applications comme les applets flash qui généralement ne le permettent pas.
Ubuntu 8.04 n’inclue pas pour l’instant d’interface utilisateur pour cette fonction, mais il est très facile d’en installer une. Pour cela, il suffit d’installer le paquet pavucontrol via votre gestionnaire de paquets ou en utilisant la commande suivante :
sudo apt-get install pavucontrol
Tapez pavucontrol dans un terminal pour lancer “PulseAudio Volume Control” (à ce propos vous voudrez certaintement ajouter l’application dans le menu).
Dès qu’une application utilisant le son est lancé, elle apparaîtra instantanément dans cette fenêtre. Vous pourrez alors utiliser les ascenceurs pour chaque application et la sortie sonore sera automatiquement ajutstée. Dans les autres onglets, vous pouvez ajuster le son de manière globale.
PulseAudio mémorisera vos réglages au prochain lancement de l’application, donc n’oubliez pas de remettre le volume à 100%.
UbuntuHCL.org
1406 days
A new site has been launched today within the large community of Ubuntu related web. This new site is providing users with a reference for all hardware compatibility under this GNU/Linux distribution.
This will give users more chances during their migration to this system, and will federate knowledge on hardware compatibility. Search can be performed through brands or categories of hardware.
The only question is, why it didn’t exist a week ago when I had to install my brand new Acer laptop ?
Update du test des applications en ligne
1457 days
Et voila, je viens de decouvrir un nouvel outil, qui se nomme splashup, interface extremement soignée, il gère les calques, l’envoi et la sauvegarde de fichier depuis diverses applications. Toutefois, il semble ne pas avoir autant d’effets possible que Fotoflexer, il reste néanmoins un outil interessant pour de simples retouches type contraste, couleurs, flou, etc…
