Anything related to Linux

DNS performance benchmarking update

on December 14, 2009 in Linux with no comments by

A few days ago I posted a short blog about DNS performance benchmarking by Google using namebench. After the rather surprising results, I decided to replace the primary upstream DNS server with OpenDNS.

Once I had run the namebench too again, the results were showing a huge leap in performance. But strikingly, BT’s DNS servers were still faster than my own local servers. Jonathan, the resident monkey, also commented about this based on his own tests. It seems that there might be something amiss with the namebench tool (and I shall dutifully point this out to Google, to see what they have to say). read more →

DNS performance benchmarking by Google

on December 12, 2009 in Linux with 2 comments by

Today I came across namebench by Google, a DNS (domain name system) benchmarking tool and gave it a try.  To my surprise, namebench determined that a DNS server owned by BT and located in the UK was faster than my own or my provider’s DNS servers, both of which are located in France.

In fact, this is the damning message that namebench gave me: read more →

Quick Debian/Ubuntu networking tips

on October 20, 2009 in Linux with 5 comments by

Like anyone else, at times I forget how to do certain things when it comes to networking.

Here are a few reminders / tips specific to Debian and Ubuntu.

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Compiling NginX on Debian / Ubuntu

on September 7, 2009 in Linux with 3 comments by

I really like the efficiency and simplicity of the NginX web server (pron.: “Engine X”). In one of my previous blurbs, “NginX and Apache, but no memcached”, I gave some numbers on how well it performed on a no-frills server.

For Debian and Ubuntu users installing NginX couldn’t be easier. Simply issue the command  apt-get install nginx command and do some basic configuration.

However, the version availble in the Debian and Ubuntu’s package repositories has not been compiled with IPv6 support. If you need this, or if you prefer to use bleeding-edge technology, then compiling NginX is the solution. read more →

NginX and Apache, but no memcached

on August 31, 2009 in Linux with 7 comments by

I’ve been reading a few other blogs about how some people have implemented NginX as an accelerator for their Apache-based websites.

NginX outperforms Apache on small- to mid-range servers when it comes to static file handling, particularly because it is event driven.

The downside of NginX is that PHP can only be used with FastCGI. In general, most how-to’s explain how to implement PHP FastCGI with NginX using TCP. This is adding extra overhead and slows PHP to a crawl. A better solution is to use the UNIX sockets instead, which is explained well in Till’s blog.

But even using UNIX sockets, the PHP FastCGI and NginX combination is not as fast as Apache can handle PHP requests. For this reason, NginX can act as a great accelerator for static files while Apache deals with all the PHP requests. Even with the extra TCP overhead between NginX and Apache, this makes for quite a speedy combination.

Thinking logically, some people figured that loading static files from RAM memory instead of the harddrive must make things even faster. But that really depends… read more →

Guide: Firewall and router with Proxmox

on August 31, 2009 in Linux with 48 comments by

Firewall and router with ProxmoxBy default Proxmox does not come with a firewall, which may leave it and your virtual servers exposed to the elements of the Internet.

An additional issue arises when a hosting provider blocks servers if unauthorized MAC addresses are detected. As Proxmox’s bridged network creates and exposes MAC addresses for its virtual network interfaces, this may cause your server to be blocked from the hosting provider’s network.

To combat both this article will describe how to create your own virtual network with firewall protection using Shorewall, a popular and effective firewall / router software package.

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X server with sound inside an OpenVZ / Proxmox container

on August 24, 2009 in Linux with 3 comments by

Generally when using X-based applications inside an OpenVZ or Proxmox container, the host node will run the X server and the container will use X forwarding through SSH to run the application. An article at the Open VZ Wiki explains this in more detail.

However, I wanted to have an X server inside the container itself. Moreover, it should also have support for sound (ALSA). The reason behind this is to have a container capable of running FreeSWITCH (a high performance VoIP switch similar to Asterisk) with the Skypiax trunk (for Skype connectivity) fully independent.

There are various methods of implementing the X server inside an OpenVZ or Proxmox container, especially if no direct video output is required. However, there is very little information available on how to enable sound inside an OpenVZ or Proxmox container. This article will explain how to do this. read more →

Guide: Installing OpenSolaris on a remote dedicated server

on August 24, 2009 in Linux with 6 comments by

There was an article at the OVH Wiki that outlined how to install OpenSolaris on a dedicated server with the help of Linux and Xen. This article is of special interest to those who have a dedicated server at a hosting company, but do not have the option to install anything but a Linux distribution.

Unfortunately, that particular article attracted a number of Wiki spammers and it disappeared in a sea of links to unscrupulous websites. I am reviving that article here, for those interested.

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